Follow TV Tropes

This is based on opinion. Please don't list it on a work's trope example list.


Nightmare Fuel / Warhammer 40,000

Go To
"Between the stars the ancient unseen enemies of mankind wait and hunger. Every voyage into the nothing is a confrontation with horror, with the implacable things of the warp, and with man's own innermost fear."

Forget the power of technology, science and common humanity. Forget the promise of progress and understanding, for there is no peace amongst the stars, only an eternity of carnage and slaughter and the laughter of thirsting gods.

Have we exhausted all possible ways to divine the future? How many scribes must toil to scratch their visions onto ancient parchments so that we might catch a glimpse of hope? Or are we to suffer only the pangs of despair as yet more horror is let loose on our dreams? Or does the seeking itself give birth to more insanity than man can cope?

The Dark Future Beckons!

Fear the unknown!

Being the bleakest setting in all of fiction and the origin of the term Grim Dark, it's no surprise that Warhammer 40,000 is positively drowning in horror and then some. And we wouldn't have it any other way.

Works with their own Nightmare Fuel pages

WARNING: Per wiki policy, Spoilers Off applies to Nightmare Fuel pages. All spoilers will be unmarked!

    open/close all folders 

The Forces of Chaos

    The Chaos Gods 
  • Four Gods of Chaos, countless ways to make your spine tingle. And the most horrifying thing is that they exist by feeding on the emotions of living beings. Living beings cannot help but feel things, and so we will never truly be rid of them, so one of the few ways to ultimately defeate them is to kill every single living being in the galaxy. This is the goal which Necrons (at least pre-retcon) want to accomplish.
  • Nurgle loves his followers, he really does. And he'd probably be jolly good grampy to you, if you'd just join up. It just so happens he shares his love by infecting you with so much disease you end up a bloated rotting zombie-like thing which is in so much pain that it can't feel any other pain. But Papa Nurgle loves you, so it's all fine.
    • And they love it. Other servants of Chaos are intensely suffering or blindingly insane or "merely" a mindless spawn, but Nurgle followers genuinely enjoy being followed by clouds of plague flies and having their organs dragging on the ground, and nothing would please them more than giving you a biiiiig hug so you can enjoy it too. Come to Papa Nurgle~
      • It is similar in some ways to Nineteen Eighty-Four, where all citizens get to be brainwashed by the oppressive Party and end up worshiping the very organization that has made their lives miserable. Sure, the specifics of the methods to that result may be different, but still, Nurgle tampers with your mind and transforms you into a mindless zombie drone worshipping diseases.
    • Nurgle's Rot, perhaps the most gruesome of the nightmarish Chaos powers, infects almost all of his followers and can be transferred with a single touch, inflicting the poor victim with a concoction perfected by Nurgle himself to cause the most agony while still keeping them from death, many pledging themselves to Nurgle just to end their suffering. It also contaminates the soul as well as the body, each person killed by the Rot creating another Plaguebearer in Nurgle's "garden", the more they resist death merely resulting in a more powerful Plaguebearer. Oh, and said garden may include one very special favored guest, who Nurgle force-feeds all his creations to just to see how powerful and harmful they are.
    • The only being able to cure Nurgle's creations, Isha, the Eldar goddess of life. Who Nurgle is trying to convince to marry him. And she's still better off than with her previous "suitor," Slaanesh, about whom see below. But since she can cure any of Nurgle's creations, that means she cannot die, so the experiments will never stop.
      • At least Nurgle was rescuing her, which is saying something. He was able to do so while Slaanesh was busy slaughtering the rest of the Eldar pantheon. And she uses her position to whisper cures to Nurgle's diseases to mankind. It's slightly salved by the Fanon that they love each other.
    • Plague Marines. Dark, bubbling, deep, filthy, scary.
      We...[gasp]... are Death... [rasp] and Decay... [wet gagging]...
    • The Death Guard. Take the best qualities of the Space Marines, combine them with 28 Days Later style zombies, and you'll have something akin to a Death Guard trooper. Scariest of all (both in tabletop and in fiction), they are Determinators - they'll never stop coming at you until you're either a festering mass of plague or dead.
    • Beasts of Nurgle are abhorrent, sluglike creatures dripping with toxic ooze, spurting dangerous gases from chimneys on their back and dribbling acidic spittle. But these things are not insane, dribbling wrecks - they have the minds of cute, playful puppies, who only wish to give the enemy bone-crushing hugs and slobber all over them. As if this wasn't bad enough, they have no concept of death - once they kill, they are momentarily disappointed by the fact their new playmate has gone still, then ooze over to another foe to make a new friend.
    • The Rot Flies of Nurgle. Sometimes, a Beast of Nurgle starts resenting that all its human playmates either won't play or actually chase it back to the Warp. And that resentment just builds and festers until the Beast spins a cocoon and pupates. What hatches is a monstrous, plague-ridden, slime-dripping fly-daemon that is now actively malicious and cruel. They favor going for the heads of their enemies; either snipping them off with giant mandibles or using a disgusting proboscis to suck their victim's head so hard they slurp out the entire spine in one gulp. They digest these skulls inside their foetid bellies and then spit them as projectiles. But some people, they hold a special grudge against who the Rot Fly swallows them whole, trapping them inside its worm-riddled, stinking, pustulent guts forever.
  • Khorne. He'll give you martial might beyond compare and a will to dominate that knows no bounds, which translates into frothing berserker strength. All he asks for is blood. Lots of blood. Your enemies', your friends', yours - he isn't picky. Khorne cares not from whom the blood flows, only that it does.
  • Tzeentch, god of chessmasters, manipulative bastards, and the Gambit Roulette. He'll grant you sorcerous powers beyond your wildest dreams, visions of the future, and the ability to craft schemes of dizzying complexity. Unfortunately, he's called the Changer of Ways for a reason, so you might get a mutation. Or two. Or twenty. Since Tzeentch is above all else a god of Chaos, despite his patronage your schemes may fall apart, especially if your mutations go so out of control you regress into a mewling, mindless Chaos Spawn. But don't worry. That was part of his plan all along.
    • The Thousand Sons Legion learned this the hard way. Soon after being banished to the Eye of Terror, all of them began accumulating so many mutations that some weren't so much "unrecognisable" as "oh god oh god what the hell is that". Their most powerful sorceror Ahriman cast a massive spell in an effort to prevent certain destruction, and he succeeded in halting the mutations by converting most of the Legion to dust and sealing them inside their armour forever, transforming them into mindless automata. However the spell also turned the sorcery of the minority with even a little psychic power up to eleven, so it's all good.
      • The best part is that the Thousand Sons primarch turned to Chaos (and Tzeentch) to save his legion from extermination. At the end he learns that Ahriman's fiasco was all part of Tzeentch's plan.
      • Every time the Thousand Sons commit some sort of atrocity, remember this: Primarch Magnus the Red tried to warn the Emperor of Horus' treachery via sorcery, which the Emperor didn't like so much (Magnus's psychic message inadvertently irretrievably wrecked a critical project that the Emperor had been working on for decades), and thought that his favorite Primarch betraying him was preposterous. Instead, he believed Magnus was trying to betray him and sent Leman Russ to "arrest" him and bring him to Terra. Sure, Horus convinced Russ to try and kill Magnus, but considering how the Space Wolves regard sorcery, this was about as good an idea as sending a lynch mob to arrest a child rapist.
    • Also think about the Tzeentchian Greater Daemons, the Lords of Change. They have the power to rip souls from the strongest of men with but a glance, tear tanks in half with their immense magical knowledge, and many mortals mistake them for being omniscient from all that they know about virtually anything. And worst of all is that they can see into the immediate future because Tzeentch sends it to them, so they're nearly impossible to kill, unless Tzeentch sent it false images of the future and let you kill it. Congratulations: you just furthered the plans of Tzeentch.
    • Another Greater Daemon of Tzeentch is Fateweaver, once the most powerful of Tzeentch's Lords of Change - until Tzeentch hurled him into the Well of Eternity, where the events of all time both begin and end, in an effort to gain perfect knowledge of all things. This had killed every Lord of Change prior to Fateweaver, and reduced him to a hunched and weakened shadow of his former self. It even forced the growth of a second head, and both heads answer any question asked of Fateweaver. One will be the truth, the other an equally believable lie. Tzeentch has a few dozen Lords of Change on hand to record every word he says just to make sure they don't miss anything.
    • And the Changeling, who has such absolute control over his ability to shapeshift that he's lost his original form. Only Tzeentch knows what it is, and he doesn't tell him to keep his control over him. That doesn't stop him from being an exquisite manipulator in the name of Tzeentch. Once, a rogue Imperial governor summoned the Changeling and asked for an artifact to break the siege that the Dark Angels were laying upon him. The Changeling handed him a device, then vanished - and was replaced by a squad of Terminators. He'd handed the governor a teleport homer. Broke the siege, though not the way the governor wanted.
    • Tzeentch doesn't have an ultimate plan. As he is the very embodiment of scheming and change and transformation; he doesn't need a goal to achieve. He exists, literally, just to meddle with things and see what happens; he can never lose because he's not trying to win. No matter what the outcome is, so long as something keeps happening, Tzeentch is winning — he's just got to set the wheels in motion so that the universe keeps changing.
      • In a way, that's a bit (however tiny) of good news for everyone else, because if he did have some ultimate diabolical goal (such as enslaving the souls of ALL humanity at once), he could easily do so since he obviously has the power and especially foresight for it. Thank the Emperor that he's too "random" for that.
    • The most terrifying thing about Tzeentch is perhaps the very emotion that gave birth to him. Tzeentch is the God of Hope. While the other gods can be defeated by simply having a mental fortitude to never indulge to the extreme, Tzeentch will live on so long as there's hope for a tomorrow. To annihilate him, all of the galaxy must submit to absolute despair and, quite literally, hope for nothing. This is most tragically illustrated by Ahriman, who still believes that he fights in the name of the Emperor and for the betterment of mankind, and that he is not a pawn of the gods. He is only allowed this because, in his denial, he is the greatest embodiment of hope in the universe. The fact that Ahriman is Tzeentch's Chosen Champion should tell you how utterly screwed he (and the rest of the galaxy) is.
  • And then we have Slaanesh, the Dark Prince of Pleasure. (S)he'll give you sensations beyond your imagination, pleasures and pain beyond mortal understanding, which your warped body will eventually become acclimated to, forcing you to take increasingly extreme measures to reach similar highs, even as your senses become dull. Eventually you'll be undertaking ever-more disgusting atrocities in an attempt to stir your jaded emotions, while you hardly feel anything at all.
    • The Emperor's Children Legion serves Slaanesh exclusively, and are essentially Super-Soldier versions of Dark Eldar as a result. During the siege of Terra, when the other Legions were assaulting the Imperial Palace, they decided their time was best spent killing millions of the planet's inhabitants to convert them into the various drugs that composes about fifty percent of their bloodstream, with thousands more slaughtered to provide more... direct pleasure. In the ten thousand years since then they have performed more successful raids than any other Legion, devoted not to revenge or conquest or conversion but to simple pleasure. And unlike the Dark Eldar, they don't do it to prevent their soul being eaten; they just love it.
    • And then there's what happened to Fulgrim. See, sometimes the daemon won't just jump into one's head and take over. If it's Slaaneshi there's a good chance it will first have some fun with you. In Fulgrim's case, first it dug out all of his insecurities and convinced him his best friend was jealous of him. Then it convinced him to kill his best friend, and then it showed him that said best friend had been trying to save him all along. And then it didn't destroy Fulgrim's mind, because it wanted him to watch what it would do, 'cause his suffering would be fun.
      • It gets even worse. All of the atrocities "Fulgrim" committed over the centuries afterwards just kept getting more and more horrific and flamboyant as time passed. Killing his best friend also just knocked down the last barrier between any semblance of sanity and embracing full-on corruption. Even though he got bodyjacked for a time, Fulgrim, in the end, turned out to be stronger-willed and more debased than a daemon that was depravity incarnate! He turned the tables and did all of his horrors himself! If that didn't make you say "Holy shit"...
    • All of the Chaos Gods have Chaos Marines devoted specifically to them. Slaanesh's are the Noise Marines; Sense Freaks so jaded and burnt out that they can't feel anything any more. So they take to the battlefield wielding sonic weaponry, because the resultant cacophony is the only thing that can provoke any reaction in them any more. These have absolutely horrific effects on anyone they hit with them — imagine a sound so intense that your flesh literally melts off your body from the vibrations. These even managed to be creepy when the official models for them sported weapons designed to resemble guitars and electric keyboards.
    • Quoth a Slaaneshi Lord:
      Take care, lest your protests grow tiresome. I have asked for so little! Anyone would think that I have asked you to sacrifice yourselves and your sons! And yet, in Slaanesh's boundless and pleasing mercy, I have asked only for your daughters. Surely you would not deny me my small enjoyments?
  • The outcast chaos god, Malal, God Of Destruction. Yes, there's a Chaos God so bad that even the other Chaos Gods won't associate with him. Mentioned in early Warhammer fluff (including a series of comic books) and then stricken from the setting for copyright reasons, Malal favors single, powerful worshipers rather than armies, and has a special place in the Pantheon — he hunts down the other chaos forces. Yes, Malal is the chaos god of all destruction, including self destruction — his modus operandi is to pick one particularly powerful chaos champion, insert him in the exact right spot to cause as much trouble as he can for the other four, and then empower him with as much of his own energy as he can get away with — something that he steals back, with interest, from the worshiper. The resulting carnage is one of the only things keeping the other four chaos gods at bay.
    • While Malal has been stricken from the fluff, the Chaos army books have added The Sons of Malicenote , a special Chaos Space Marine army with Malal's color scheme. The story behind the SOM is horrifying in and of itself — they were particularly loyal Space Marines from a somewhat feral world, except that they had a specific knack for fighting in complete and utter silence, and their home planet had a thing for especially gory victory celebrations. A particularly puritanical Inquisitor happened to watch one of these celebrations, and while completely ignoring the similar rituals of other, more established (and thus, protected against a single inquisitor going against them) chapters, had them personally declared traitors and their homeworld destroyed — something that is heavily insinuated could happen to any other loyalist chapter who happens to get the wrong Inquisitor visiting them. In fact, it's implied that the only thing that caused the Sons of Malice to fall was the fact that they didn't kill the Inquisitor fast enough. In other words, the Sons of Malice and the millions of people living on their homeworld were screwed over by the Warhammer 40000 version of an Obstructive Bureaucrat.
    • It's more violent than most cannibalistic chapter rituals. In the short story The Labyrinth from Heroes of the Space Marines, they are depicted eating slaves alive. The rest of The Labyrinth is quite scary, what with the Body Horror of the transformed marines and it ends with the protagonist, having run the titular Space Hulk's gauntlet, being sacrificed with the ten other victors to summon Malice (renamed due to copyright) himself.
    • Another thing about Sons of Malice. They have continued a war against both the Imperium and the armies of Chaos at the same time, for centuries and winning most of their engagements, while being insanely outnumbered and outgunned and without any daemons or heavy support. How the hell they can accomplish this nobody knows, mostly because there are usually no survivors.
    • There are also some implications, that Sons of Malice are seemingly acting like a beacon for all worshippers of Malal as they are often supported by solid numbers of cultists and fallen guardsmen, not to mention mutants.
  • All Chaos gods can be taken as corrupted versions of otherwise positive emotions:
    • Slaanesh as a corruption of Love or Happiness. As long as someone loved another, they're contributing directly to Slaanesh. And if they loved even a bit too much, they may be approached, and the corruption shall begin.
    • Khorne as a corruption of Bravery or Glory in the Grim Dark universe where there is only war.
    • Tzeentch as a corruption of Hope or Wisdom. Any who hope for deliverance, any who wish to learn more to make a better tomorrow, will fall into Tzeentch's clutches.
    • Nurgle as a corruption of Acceptance or Friendship. Friendship is pretty much guaranteed between people. "Acceptance" is the central dogma of most of the uncountable masses of the Imperium.
    • Malal is a corruption of Justice. It's specifically stated that anyone who hunts Chaos too effectively, anyone who lets the hunt consume them, has a chance of being approached by Malal.
    • This also resulted in one of the biggest horrors in the form of Castellan Crowe: to keep his Daemon-blade inert and safe, Crowe basically eschewed every part of his life. He feels no joy from victory, no sense of camaraderie, no fulfillment or desires. He is not even allowed to feel sadness at all of this, and is locked away in a solitary room whenever not on duty. One of the few servants of the Imperium who can possess a Daemon Weapon without corruption, but he can no longer be anything. And even then, it's implied that Crowe is helped out by the Emperor himself, as well as an inborn self-discipline that no other Grey Knight can ever aspire to.
  • In the Horus Heresy novella Aurelian, Ingethel the Ascended tells Lorgar, whose Legion masterminded the Horus Heresy, that those who worship the Chaos Gods will be accepted into their power, and those who reject the Chaos Gods will be devoured by daemons. This concept of the afterlife is a major part of Chaos Undivided, and is why the Word Bearers pride themselves on knowing the truth. Unfortunately, it's also Blatant Lies. In Deliverance Lost, during the aftermath of the Drop Site Massacre, a Word Bearers vessel trailing the Raven Guard's last battle-barge gets pulled into the Warp. Do those within, who have dedicated their lives and souls to the Chaos Gods, get taken to a pleasant afterlife? No. They're devoured and tormented by daemons just as much as someone who rejects Chaos. There's a reason Chaos is dubbed "The Bad Guys" of the series. It's because the Chaos Gods literally don't give a damn about their followers.
  • The Chaos Gods themselves represent corrupted Chaos, not just chaos itself. As mentioned elsewhere, Chaos is affected entirely by the emotions of sentient beings in real space. Ever wonder why Chaos is Chaotic Evil and not Chaotic Good or Chaotic Neutral? It's because that the galaxy and every living thing in it are just that screwed up. The fact that all factions are Ax-Crazy, manipulative, xenophobic, omnicidal, is why Chaos is the absolute worst of all of them. No one will ever "win" Warhammer 40000, because evil itself exists and it has already won. It won a long time ago.
    • Although long-since retconned, an old timeline showed three of the current Chaos Gods coming into full being somewhere between the eighth and fifteenth millennium. This is also the time-frame when Mankind first began to prolifically expand into the stars, and saw an unprecedented boom in population numbers. Before this point, the Warp was of course Chaotic, but good gods (such as the Eldar pantheon) existed as often as evil ones. After this point it became infinitely more hellish. Even after the retcon, although not explicitly stated, it's implied that the current state of the Warp is the fault of Mankind due to our high Warp presence and tumultuous minds.
    • It should be noted that all sources of canon only refer to the Milky Way. While Mankind has become top predator of the Milky Way, following in the wake of countless races before them, it is implied that few if any races managed to get to other galaxies (the only known being to try is the Silent King of the Necrons during his attempted exodus). While this implies that the warp may be less tumultuous in other parts of the galaxy, it also make the Tyranids more scary (see below). That Necron King stopped his self-exile out of fear for the entire galaxy when the Tyranids came to the Milky Way, becoming the first known species of intergalactic travelers. Note that these purely biological creatures succeeded where other species failed. Species that were so technologically advanced that they were considered virtual gods.
  • Among all that, there is still one more lingering fact; those 5 named chaos gods are simply the most powerful of the chaos gods. Some of the more pessimistic delvers of hidden knowledge have concluded that when the Emperor of Mankind dies (and he will) the resultant Fall of Mankind to Chaos will not only open a rift into the Warp the size of the entire Galaxy but will create the final and mightiest Chaos God, who will corrupt, torture and enslave all remaining sentient life as they descend en masse into a screaming, eternal hell. Sweet dreams.
    • Also note that Dan Abnett provided more information about this subject (if they are considered canon and the information brokers weren't lying) in both the Eisenhorn and Ravenor series. In the Eisenhorn's series, a demon speaks of a Demon King who at one time was a rival to Tzeentch who, while independent, sought to topple the Lord of Tricks. Implying that the gods could be killed and replaced. Furthermore, the Big Bad in Ravornor claims to worship the Eight. He seems to imply that there a total of 8 chaos gods (of mankind, so not counting Gork and Mork [dual gods of the Orks] or the C'tan [who are really just energy beings with an unfathomably immense knowledge of/power over the laws of the physical universe]). The four major gods are the most powerful while Malice would be the strongest or most influential of the "weak gods". It is unknown how these hypothetical weak gods would compare to the Daemon Prince Champions of the major gods. One still has to wonder what the remaining 3 gods represent... note 
  • Another of the renegade Chaos gods is Necoho, the Doubter. What does he represent? The struggle against the very concept of gods or religion. Yes, Necoho is the god of unbelief. While this paradoxical nature means he has a small following and he's not very powerful, his existence alone shows that any attempts to destroy chaos are futile. Even if the entire galaxy were somehow magically convinced that Tzeentch, Nurgle, Khorne, and Slaanesh weren't real, something would take their place.
  • There is a theory that all Chaos gods are nothing more than aspects of one true Chaos God: the Great Unnameable One, the Lord of Chaos, and so on. If it's true, imagine what can happen if this being awakes...

    The Warp 
Possibly the ultimate example of Hyperspace Is a Scary Place, the Warp, also known as the Immaterium, is an alternate dimension that manifests the thoughts and emotions of all conscious life, and implied to serve as the 'afterlife' of the galaxy, if not the entire universe. It's a Hellish churning realm brimming with daemons and the aforementioned Chaos Gods. Time, space, and logic have absolutely zero meaning in this realm. Every single dream, nightmare, metaphor, thought, feeling, and idea by any sentient being in real space has a physical manifestation within the Warp. There is an embodiment for absolutely everything imagined by anyone, including Things Man Was Not Meant to Know. It is ruled over by the four god-like incarnations of Rage, Deception, Despair, and Lust.
  • Traveling through the Warp is the most common method of Faster-Than-Light Travel for the space-faring civilizations of the galaxy. For a ship of the Imperium, this involves tearing a hole in reality and sending your ship hurtling into this nightmare void. Only, in the Warp, the nightmares really can come and get you. Here's a lovely description for how the Imperium does it.
  • One of the older bits of fluff (most likely written before the Horus Heresy series came out) casually mentions that at the dawn of interstellar travel humanity tried various methods of faster than light travel - and going through the Warp was apparently the best option.
  • The 1997 film Event Horizon is often said to be set in WH40K, being about a faster-than-light travel experiment that causes the crew to slaughter each other in an orgy of madness and glorification of chaos (lower case). It is far too tame however, as the crew basically kills one another when driven insane by the visions that hell forces on them. In the Warp, sure, that can happen, or you can get killed by the actual, tangible demons.
  • Chaos gods, worshipers, cultists, demons, vehicles etc all spread absolute fear and terror and are the stuff of nightmares. So then why should their very homes be any different? Each of the four Chaos gods resides in their own domain within the Warp whose landscape defines their characteristics.
    • Tzeentch's Maze has no defenders but does that mean you're safe? Oh hell no. It is basically a giant swirling ever-changing maze where the laws of physics, gravity, reality or ANYTHING are virtually non-existent. Should you be stupid enough to somehow wander into the Maze of Tzeentch, expect to find yourself lost on your very first step and watch the path you took suddenly disappear forever. Then as you wander aimlessly in the ever-changing maze, which can include colors and objects that doesn't even exist in the universe, you will slowly and surely be driven into complete madness and despair and you soon die of insanity. Oh and since the Maze is within the Warp, when you do die your soul is gonna remain there so there's no escape from it even in death.
    • Khorne's realm is basically Valhalla on steroids; he sits on a throne of brass atop a mountain of skulls, which grows with every death in combat. His chamber is lit by dark flames which consume the souls of deserters; warriors who died in their sleep are forced to man his war machines for eternity. His citadel is surrounded by a moat of blood, and features a battalion of Orks in a constant state of war, constantly resurrected to fight. The Orks, however, think they've found paradise.
    • Nurgle's realm is a garden of every hideous form of life; it swarms with flies and rot and is choked with poisonous thorns and crossed by sloshing mires. Great groves of giant fungi and wilted leaves form the bulk of the scenery. At its core, Nurgle sits at his cauldron of disease, a swirling maelstrom of affliction as large as all the oceans in the galaxy, at which he concocts his latest plague, first testing it on a captured Eldar goddess he keeps imprisoned next to him, who feels every thrum of raging agony but, because she has the power of healing, can restore herself to health after every infection, whereupon he will promptly infect her again. And again. Forever.
    • Slaanesh's realm is the Palace of Slaanesh, a series of six concentric circles each tempting you to a different sin. It does not look too overtly dangerous unlike the other Chaos God's realms, but that is the purpose — once you fall into their traps of desire, you're dead. The Circle of Avidity has mountains of gold cascading with waterfalls of sapphires, diamonds, opals, lapis lazuli, faïence and every other precious thing, but if you even try to take one scrape of gold, you will be doomed to count gold for the rest of your life, and the jewels are all inhabited by daemons that will possess anyone who dares take them. The Circle of Gluttony tempts you with a sumptuous banquet of every conceivable culinary experience, but as soon as you put one morsel into your mouth, you will not stop eating until you explode in gore. The Circle of Carnality is every piece of erotic fanfic and carnal desire come to life, morality, legality and self-preservation no object, even as you're being lured to the chopping block by daemonettes. The Circle of Paramountcy offers you roars of adulation from an inconceivably vast crowd, and the promise of absolute power over others, but play into it, and paranoia will destroy you from the inside. In the Circle of Vainglory you are tempted with your perfect self-image, where everything you ever tried to be, wished you were or secretly thought you were all along is whispered and reflected back at you in a dreamy forest landscape, but feel even the faintest stirrings of pride and this circle is your eternal prison. The last circle is a heavenly place resembling a beach illuminated by warm sunlight where all seems perfect and every moment fills you with greater bliss, but stop to savor it for even an instant and you fall into a coma to eventually die from it. You can wander here for centuries, millennia if you like, but you can't stop to enjoy the warm beach scape for a single moment without losing it all, and to make things worse, the sands there are made of the bones of the Palace's former victims. And if somehow you have an iron mind able to resist all of this and make it to the centre, where Slannesh themself dwells, congratulations, it's all been for nought: the Prince of Pleasure is a being of such surpassing beauty no mortal can look upon them without forfeiting their soul and becoming her willing and devoted slave. Hope it was worth it. If you were to ask anyone who actually succeeded at this they would probably claim it was. After all, to gaze upon perfection itself is a great honor. Or so your new mistress says.
  • The parts of the realm not claimed by the Gods are known as the Formless Wastes, where literally anything can happen. The area is home to rivers of tar that flow through petrified woodlands beneath crimson skies, great stairways go into the heavens where they connect to themselves in an endless loop that sit alongside castles of bone and fortresses of ichor amongst limbs with pillars of fire burning over the horizon.
  • The kicker? The Warp is also known as the Realm of Souls, aka the Afterlife. Everyone is fated to be dragged into this nightmarish realm upon the moment of their death.
    • It's mentioned, however, that humans don't have presense strong enough in the warp to remain after death, so they just fade (or merge with the Emperor), and it's unknown what happens for other aliens. For the Eldar, however...
  • It is said that the reason everything about the warp and chaos reads like fairytales and legends is because the actual, tangible thing is so far from mortal comprehension that the mind rejects it and is completely incapable of describing what is actually happening. It is implied that the Chaos Gods, their followers, and everything else in the warp is simply taking on a form that won't completely destroy our minds. Considering the blasted hellscape looks like a nightmare comes true and that the general side effect of warp exposure is batshit insanity, it is terrifying to know exactly what the warp is if this is the more pleasant alternative.
  • As a result of Cadia's destruction at the climax of the 13th Black Crusade, a giant warp rift known as the Cicatrix Maledictum (among other names such as the Great Rift and Gork's Grin) ripped open across the galaxy from the Eye of Terror to the Hadex Anomaly, essentially cleaving the imperium in half. While it appears as an tainted scar in the sky for the worlds on Terra's side of the rift, the worlds on the other side of the rift, in the so-called "Dark Imperium" have it far worse - for them, the Great Rift is the very gates of Hell. Additionally, the formation of the Great Rift obscured the Astronomican, making warp travel and astrotelepathic communications all but impossible, plunging the Imperium into a second Age of Strife.
  • Space Hulks. Space Hulks are a mish-mash of multiple ships that got stuck in the Warp and squished together until they are the size of a planetoid. All the different systems are somehow still working or sometimes possessed by Daemons, meaning that every corridor is dangerous in its own diffrent way, such as having a different center of gravity, or being alive, or trying to graphically sodomize you (potentially with the undead betentacled corpses of the former crew). Basically, think the ship from Event Horizon but somehow even worse.
    • The different FTL systems that got those ships into the Warp in the first place are also still working, so the Hulk will be periodically temporarily spat out into the real world, though in a variety of times and places, because that horror dimension doesn't subscribe to Space-Time or even Physics. These little real-world vacations are actually opportunities for predatory alien races to infest the Hulk, such as Tyranids or Orks (Both of which are no laughing matter, either). Or to spread any such existing infestations to nearby unsuspecting star systems and planets.
    • And yet, despite all of the above, some are still brave (or insane, depending on who you ask) to try and board these things. Why, you ask? You see, these ships contain ancient technology worth literal planets to the right buyer or of immense value to one's given faction, therefore many adventurous souls try and find fortune on these derelict nightmares. It's just a matter of finding you way in and out alive, uninfected, uncorrupted and without getting betrayed by your associates, all before the Space Hulk returns to the Warp. And you can't tell when it will happen.
  • Possibly the biggest kicker? The Warp wasn't always like this. Back in the early days of the universe, it was a fairly peaceful afterlife known by names like the Realm of Souls and Empyrean. It was during the War in Heaven 60 million years ago, when a brutal war was fought between the Old Ones and the Necrontyr and C'tan, that the realm began to shift. As the conflict eventually spiraled into a vast galaxy-wide war, one where entire star systems were destroyed and whole species were created just to fight and die, that caused so much devastation, bloodshed, and ill will to flood the immaterium that the realm itself became permanently corrupted. As bad as the many, many wars in the 41st millennium have been, they're tiny blips on the radar compared to the War that essentially created Hell itself.

    Chaos Characters 
  • Fabius Bile (formerly pictured top). It's not the fact that he's turned entire worlds into shambling horrors with his genetic experiments, or that he has a lab coat made of human skin.note  It's the fact that he spent thousands of years floating in the Warp, has pure Warp energy constantly pumped into him, and he still doesn't worship any of the Chaos Gods. In fact, he's stated that they have no more to offer him. People aren't supposed to make bargains with the Chaos Gods. That is not how it works.
    • There's one story about how he was captured by the Dark Eldar and taken to Commorragh, but he so impressed them with his knowledge of inflicting pain that they let him go, and allowed him to study under the Haemonculi. In sum, he's so depraved that even a species of immortal, sadomasochistic xenophobes have to respect his cruelty. As has been noted, this is the only time this has ever happened to anyone.
    • There's his ultimate goal, as illustrated in the Blood Angels novels. He's trying to clone the Emperor. The Blood Angels may have set his work back considerably, but as far as he's concerned, it's only a matter of time.
    • Though he hasn't yet succeeded in his ultimate goal, he has succeeded in growing a perfect, uncorrupted clone of Fulgrim, as illustrated in Fabius Bile: Clonelord. He gave it to Trazyn... in exchange for the small price of seventeen thousand, four hundred and fifty-six perfectly preserved progenoids of the Third Legion. Now imagine Bile's plans for that...
  • Typhus, the Herald of Nurgle and Host to the Destroyer Hive - Warp Flies that can enter your body through any orifice and feast on your innards, multiplying as they do so, until your body actually explodes from the pressure of all the plague-carrying insects inside you. These things swarm around him and obey his every whim. The Death Guard turned to Nurgle (they were already Chaos) when Typhus becalmed them in the Warp and unleashed the Destroyers after PARALYZING them all, letting them watch their comrades' fate and knowing they were next.
    "As the Destroyer spread throughout the Death Guard fleet, bursting the guts of the hardy space marines, Typhus came uncertainly to his feet and spoke a single gurgling, phlegm-laced word: 'More.' With that word, the flies left their hosts broken and bloated, and entered Typhus’ body like a wave. He remained on his feet, but his body was a hive of pestilence ever after."
    • Ever notice how there's never a depiction of Typhus with his helmet off (there is one of him as Typhon, but none after his transformation)? It's because the transformation of his body into the Destroyer Hive smeared his body into his armor. Under his Terminator Armor he's essentially a living, fleshy honeycomb; his skin long since fused to the inside of his armor.
  • Lucius the Eternal. If he thinks you're a worthy foe, he'll duel you. If he wins, you're dead. If he loses, you win, but if you feel even an instant of triumph or even mild satisfaction, you end up transforming into him, being bound to his armor while his soul takes you over.
    • He's a member of the Emperor's Children, which means he's a Sense Freak on equine growth hormone. Even before the Horus Heresy he'd carved up his own face, linking up the scars of a lifetime of battle to make a jagged irregular pattern, and the first time he lost a duel the codex specifically says, "Lucius' agonizing death was an experience of transcendent pleasure." So he's basically Pinhead as a Space Marine with a thing for dueling.
    • And if you had the thought "what if the person who killed him had no idea they had?", well worry some more. Once, an Imperial Guard artillery gunner fired a Basilisk shot that happened to hit Lucius, killing him, with the gunner unaware of what he had just managed. Problem solved? Nope, the artillery gunner's pride of doing his duty of killing the enemy, even though he didn't know that included Lucius, was enough to have Lucius possess him. So the person killing Lucius doesn't even have to think about him specifically while feeling pride. Just as long as he's included in the group the person is satisfied killing, that's enough.
      • Lucius: Pride and Fall shows another example of this. In the story, a lowly factory worker falls ill. After a few months of sickness and nightmares, he undergoes the process of becoming Lucius. How did this man kill an Astartes without being anywhere near him? Simple. He made the land mine that Lucius stepped on. Meaning it’s entirely possible to not even know who Lucius is and one day just transform into him because you took pride in your work...
  • Angron, Daemon Primarch of the World Eaters Legion. For one of the handful of times one of the Primarchs returned to the material realm, he descended upon the planet of Armageddon following an endless stream of daemons and proceeded to destroy everything. An entire 100-man company of Grey Knight Terminators, the very elite of the Grey Knights themselves, who are arguably the greatest Space Marine Chapter in the Imperium specifically trained to fight daemons, were deployed in response, and almost all of them died, succeeding only in banishing him back to the Warp for 100 years (and a day), at which point he might decide to try slaughtering millions again "for the Blood God". And the fact that Grey Knights were able to banish him at all is mostly attributed to the weakening warp storm, which was the only thing supporting Angron and his daemonic hordes' existence. As if the First War of Armageddon wasn't quite enough, it caused Months of Shame, a civil war between the Space Wolves and the Inquisition that cost the Imperium another Grey Knight company, numerous warships, and billions of human lives.
    • A few thousand years before Armageddon, Angron united tens of thousands of World Eaters to assault the Imperium. Close combat shock troops with almost no support ravaged Imperial space for two centuries before the Imperium withered their force and pushed them back. Angron and his force took over seventy sectors in what was known as the "Dominion of Fire" and it took a force of four Space Marine Chapters, thirty Imperial Guard regiments, and two Titan Legions to recover what was lost. Said chapters/regiments/legions spent about three millennia to retake 90% of the conquered territories.
  • And Kharn, nicknamed the Betrayer, is probably the most batshit Ax-Crazy of of them all. Here is the man who, in a fit of anger, singlehandedly shattered his own Legion's capacity as a fighting force with nothing but a flamethrower. The game reflects this - he's just as likely to go bonkers and start hacking apart his own men if he feels like it. You have been warned.
    • It gets "better"—he also shattered another legion at the same time. The two legions—the World Eaters and the Emperor's Children—were fighting over a daemon world called Skalathrax, and both sides called a temporary cease-fire in light of the deathly cold nights on the planet. Kharn, of course, was having none of that, and decided to burn the shelters that had been taken to force both sides to fight both enemies and their brethren alike to get place in the remaining shelters. Ultimately, the legions were fragmented into warbands, and Kharn has since become the embodiment of Khorne's indiscriminate rage.
    • Lore implies that, at one point, Kharn had the chance to walk away from all of it. A Loyalist Thousand Sons sorceror saw his pain and offered to remove the device that was driving him to rage. Kharn briefly realized what this meant and had considered it, but in a violent psychotic rage butchered the Sorceror. The Sorceror knew he would not survive Kharn's attack, so instead mentally related to Kharn exactly what his actions meant; Kharn can no longer blame anyone else for his pain and rage, he had the chance to cure it and chose otherwise. It's implied that this revelation broke what was left of Kharn's mind, resulting in the ruthless berserker the galaxy now knows.
  • And finally, Abaddon. He is a massively powerful, terrifying being of infinite malice and cruelty. He alone, of all Chaos Space Marines, can bring all sides together for his Black Crusades. All four Chaos Gods have agreed that he and he alone is worthy of leading their forces in the absence/disinterest of the Primarchs. He's never won, but not due to his own weakness. It's because the Imperium has EVERY POSSIBLE ADVANTAGE IN FIGHTING HIM. He commands tens of thousands, maybe a hundred or so thousand total Chaos Marines, and maybe a few million other guys, tops. The Imperium has over a MILLION Space Marines, and literally TRILLIONS, i.e. MILLIONS OF MILLIONS of other dudes. The Imperium also has way more ships and war machines, and the advantage of being totally, one hundred percent united against Abaddon, who is barely able to hold his own forces together. Not because he isn't awesome. Because the only people Chaos hates more than the Imperium are the rest of Chaos. And the Imperium only barely wins.
    • And its not only Imperium. Massive Necron and Eldar forces were reported to consistently engage Chaos forces during 13th Black Crusade. And Chaos is still gaining ground.
    • He has his own Mark of Chaos. The only others who have Chaos marks are the gods. Which hints that he may not even be human anymore.
    • A common misconception among the fandom is to depict every Black Crusade as an attempt to march to Terra that was stalled at the very beginning on Cadia due to Abaddon's incompetence. While in fact, most of the Black Crusades slipped past Cadia and went for their objectives with little difficulty. It should be noted that most Black Crusades were not an all out assault against the Imperium, but rather quite a limited operation with a certain goal in mind. The only Black Crusade that was stalled at Cadia for some time was the 13th one. note  Almost all the Black Crusades were launched to achieve a certain, very limited goal. Be it the powerful artifact, intel, resources, slaves, tech specs, destruction of some Space Marines Chapter, ancient Death Star battlestations, Abaddon will get it, ditch the his allies and fall back to Eye of Terror with his Black Legion troops. The incoming reinforcements of the Imperium crush the disorganized rabble of Chaos warbands and report about their glorious victory over the Warmaster's forces. Yet the Black Legion suffers next to no losses, gains tonnes of resources and manpower to build more ships and war machines, while the value (and danger for the Imperium) of the fully activated Blackstone Fortresses or the Planetkiller simply cannot be measured. Long Game as its finest.
    • And as the timeline moves on, Abaddon destroyed Cadia. Yes, you read that right, Abaddon did not fight in the meat grinder for nothing, he is aiming at destroying the last known planet which can hinder the growth of the Eye, and he succeeded. Not only he is no longer a General Failure, his Long Game is now set in motion as he planned. Seeing the combined might of Imperium, Eldar, Dark Eldar and even Necrons can't put a halt to the Despoiler makes you wonder who can now stop his advance.

    Chaos Legions 
  • The Iron Warriors spent the entire Great Crusade being brutalised by sieges and trench warfare. Now, after the Heresy, they've gone completely nuts and turn every single planet they live on into a super-reinforced stronghold ringed with all sorts of tanks, Dreadnoughts (which are batshit crazy, by the way) and Havocs. Relentless, merciless, and willing to infect themselves with the Obliterator virus (see below).
    • One such example of what they're capable of is known as the Iron Cage Incident. They set up base on Sebastus IV containing a keep within 20 square miles of minefields, towers, tank traps, trenches, bunkers and redoubts in order to trap their opposite numbers, the Imperial Fists. The plan starts by isolating the enemy from their orbital support, all the while dividing them up to destroy them one by one. Finally, when the remaining Imperial Fists penetrate the fortress, there's no keep—just Death In All Directions. By day six, the Imperial Fists are reduced to fighting individually and using the corpses of their brethren as cover. The siege continues for three weeks after that. The end result is that the Fists' Primarch is left a broken man, the Fists themselves are left unable to fight for nineteen years, and Perturabo (the Iron Warriors' Primarch) sacrifices the geneseed of the fallen enemy to ascend to the status of Daemon Prince.
    • The Iron Warriors are arguably the most unpleasant of all the legions for the fact that while the others are amoral and often insane bastards, they at least have some measure of humanity, martial brotherhood and honour, or at the absolute least value what they have in a material sense. The Iron Warriors only value their hatred and their opportunities to express it. In the Iron Warriors, Astartes and humans alike are just things to be fed to the legion's war apparatus. Nothing is sacred, everyone is expendable, and victory is all that matters, no matter how dirty it has to be won or how many have to die to get it. Grinding down the remains of their own dead when rations run low is common practice. Even Chaos itself is just seen as a weapon to be used.
    • Their own homeworld, the daemon world of Medrengard, is an accurate reflection of its owners: a barren wasteland carved apart by trenches and fortresses so labyrinthine that they defy even basic geometry. Every day, beneath a black sun, the warbands of the Iron Warriors fight against each other for dominance, hating each other almost as much as they hate the Imperium. Their animosity towards just about everything in the universe is reflected in their environment as well, where even the planet's air and soil is saturated in pure hatred. And that's not even getting into the unspeakable horrors they keep locked away beneath the planet's crust...
  • Night Lords get their giggles from psychologically torturing entire planets. One piece of fiction has them crucifying and eviscerating loyal Assault Marines, then nailing the iron crosses to the front of their tanks. And the Assault Marines were still alive.
    • One of their feats of evil includes hijacking an Imperial warship sent against them and taking it into low atmosphere, completely intact. People flooded the streets, rejoicing in the belief that they had in fact won the battle. Until the airlocks opened and rained the body parts of the unfortunate crew upon them - along with their flayed skins.
    • In another piece of fiction the Night Lords invaded a hive city (a planet covered in mile high cities) and hacked into the telecommunications networks and broadcast the murder, death and torture as it happened. The Imperium reports after the attack stated that fully one-third of the population died from fear itself. Total. Nervous. Shutdown.
      • Also, in the same book, they came up with a plan to shut off all psychic communication and Warp navigation in an enormous area of Imperial space. How they achieved this? Flaying every astropath on the hive planet, keeping them alive for hours afterwards with medical treatments to prolong their agony, and finally killing them by exposing them to Navigator Octavia's third eye, which released the build-up of psychic energy that their suffering had created. And the strain of that almost killed her as well.
    • The Night Lords were nuts even before the Heresy. After Konrad left, his homeworld of Nostramo fell back into the hands of criminal syndicates, who sent the worst psychopathic criminals offworld, part because they were the most able to survive Astartes training, part just to get rid of them. True, he regrets it at the end and hated what the legion became, but one must remember: the Primarch himself was considered a homicidal psychopath before becoming Primarch, and he hated what the legion has become. It's even suggested that he allowed himself to be killed by an Imperial assassin because he was so deeply and utterly horrified by what he himself had become. The entire legion basically runs on this trope.
      • He let himself be killed as vindication; he had been Dreaming of Things to Come ever since he was a child, with one of the dreams being the exact circumstances of his death. He allowed the assassin into his chambers, watched her walk up, and flat out told her in only slightly more grandiose speech that "everything I have ever done is proven to be in the right by your presence here." This includes betrayal of the Imperium, and the destruction of his own homeworld. And he's RIGHT. Yikes.
    • Said Primach, Konrad Curze, was a combination of Batman, The Punisher, Kurtz, and Satan, as a demigod. His Chapter learned well.
    • The Night Lords were originally depicted as extra-awful psychopaths back when Space Marines in general were often recruited from maximum security prisons. It was later changed that Space Marine indoctrination had to begin at an age of between 10-12, coinciding with the onset of puberty. The Night Lords are still, canonically, depicted as being gathered up from amongst groups of depraved murderers and maniacs, despite not being old enough to attend high school.
  • Word Bearers are the Imperial zealots with all that fanaticism turned to the Dark Gods. And they're the ones who kicked off the Horus Heresy - in other words, the entire fucked up state of the 40K universe? Lorgar's fault. The entire hell-universe that would give H. P. Lovecraft night terrors is Lorgar's fault. Even the Imperium's current state is Lorgar's fault, because he wrote the original Lectitio Divinitatus tract slash holy book.
    • Backstory from the Dark Crusade campaign included a pious individual named Virgilius, some Vlad the Impaler-style human sacrifice, and seven "volunteers". One of the sacrifices chickened out at the last minute, but luckily two of his companions were able to catch him and hoist him onto his pike anyway (in his screams he “issued the fifteenth curse,” which the temple presbyter took as a good omen). Once everyone else was “positioned,” the presbyter had one last concern that Virgilius would refuse to do what was required of him, but he needn’t have worried: Virgilius climbed onto his pike without a qualm, and then opened his abdomen with a consecrated knife and let his entrails fall to the floor. The reason for all this? The sacrifice of eight souls this way opened a portal to the Warp so that Eliphas the Inheritor could start his campaign on Kronus. That’s right: just requesting military support from the Word Bearers involves ritual murder-suicide. It might not be canon, but holy shit it’s illustrative.
  • Emperor's Children. Pray to the emperor that you never meet these guys. These sick bastards will rape you, your family, and then liquify you all down into combat drugs. And they will most likely stitch open your eyes and ears beforehand, so you can experience it all in mind-blistering detail. Why? 'Cos it's fun.
    • To build on this - the Emperors Children were "gifted" with vastly more sensitive pleasure centres in the brain, allowing them to experience absolute euphoria from merely pleasant actions. The downside? The effect wears off a couple of times after the action is carried out. So over the course of time, they've been gladly resorting to increasingly morbid and sickening ways to stimulate themselves, be it through extreme sado-masochism, self-modification, hyper-narcotics or murdering people in extremely prolonged and convoluted ways that would even make the Crossed wince in disgust. The fun part? Most of them passed the point of currently-known depravity by the end of the Heresy. Its been ten thousand years since then. What the hell are they into NOW?!
      • 10,000 years in real space, but inside the Eye of Terror time passes slower, or perhaps sideways. It might've been only a week to some of them.
      • The person who made Emperor's Children such freaks? Fabius Bile. It's he who gave them these pleasure centres. So, aside from Laeran corruption, he effectively doomed his Legion to Chaos. But it's nothing new.
    • The terrifying thing that sets the Emperor's Children apart from other Chaos factions is that they rarely (if ever) have an end goal. They do what they do solely for the sake of pleasure, and will continue doing whatever it is they're doing until they get bored. This was most notable during the heresy, where instead of supporting their brother heretics in besieging the Imperial Palace, the Emperor's children was in the countryside, raping and killing the civilians for fun. The only reason they stopped was because the other legions got driven away by Horus's death and they decided to end the party there. These guys are like the Dark Eldar but with the timer on their lives removed.
  • The World Eaters are more straightforward in their beliefs and worship of Khorne. Kill, kill and kill. Run out of enemy warriors? On to the civilians. Out of that? On to the next planet. Can't do that and blood is demanded? Turn on your "allies". Still unsatisfied? Tear yourself to pieces for Khorne cares not from where the blood flows, only that it does.
    • Even before they were taken by Chaos, the World Eaters emulated their Primarch by installing the "Butcher's Nails" into themselves, essentially lobotomizing themselves so that they feel pain instead of any emotion other than anger. And they still weren't angry enough for Khorne, who turned them from "howling mad" to "snarling, spit-foaming anger."
    • It's really telling that (as Bricky noted) the "kill everything" people are some of the best Chaos Marines to be taken captive by. At least they let you have the release of death, unlike some others.
  • Death Guard Plague Marines have long since given up on such concepts like hygiene, not having diseases that can rot tanks or having their intestines in the correct side of their abdominal cavity. Even worse is the extremist splinter faction named The Purge who skip all of that cycle of life thing and get straight to the killing. Their only goal is to kill everything in existence in the Plaguefather's name. The Death Guard have biochemical weapons that can literally melt through buildings. Oh and their Blight Grenades are made from diseased heads.
  • Thousand Sons are split into two categories: Egomaniacal sorcerer, or dust in animated armour.
  • Black Legion are the apex of this. Because they are all of the above. The rampaging Khornate psychopaths? They have those. The sadistic Slaaneshi cultists? They have those. The silent, decaying infected Nurglite monsters that look like zombies in power armour who cheerfully declare you will be happy in the Plaguefather's embrace as your skin melts away? They have those. The manipulative and diabolical Tzeentchian sorcerers and piles of of dust in animated armour? They have those. The sadistic Raptor cults and terror obsessed maniacs? They have those. The utterly selfish and uncaring siege masters whose only values are being able to identify what is useful to them and for how long? They have those. The fanatical Dark Apostles? They have those. They have access to every single horror in the Chaos list and then some. The Black Legion has given up any identity other than their dedication to the destruction of the Imperium in favor of a new domain for humanity where the Dark Gods are the objects of worship.
  • Alpha Legion are about the only ones with a sympathetic motive that they may or may not have lost over the past ten millennia (currently their modus operandi tends to be about enforcing a particularly brutal brand of Lawful Evil). However, nobody really knows their motives, their leadership, or really anything about them at all. Their Primarch, Alpharius, was the youngest and last discovered, more or less ignored by the others (except Horus) and as it turns out, may have a twin brother, Omegon. Alpharius may be dead; nobody's sure, because it wouldn't slow them down. The Alpha Legion's mascot is the Hydra, and their motto is "Cut off one head, two more replace it."
    • The really scary thing is that it's very strongly hinted that the Core of the Alpha Legion at least, is well and truly loyal to the Emperor despite their Daemon usage, chaos cultist cannon fodder, fondness of spikes, and the occasional warband that has lost sight of their goal and truly has fallen (Like Lord Bale's or Fieravious Carron's). Everything they do, they do for the Emperor.
    • As it turns out, their motive itself reveals some added horror—it was revealed to Alpharius that if Horus were successful, humanity would have been wiped out within two generations, but Chaos would ultimately be broken. If the Emperor won, however, he would be trapped within his own body on a golden throne, and humanity would stagnate and decay over the course of the next 10-20 millennia, enabling Chaos to overrun the entire universe. Welp.
      • However, in Vulkan Lives, Eldrad Ulthran, a real Eldar Farseer, indicates that it may be wrong, and that a military victory for the Imperium may be the best outcome.
    • As explained further down, destroying Chaos is difficult, if not impossible. So the Alpha Legion have a goal based solely on Insane Troll Logic: Chaos must be defeated so save humanity. Chaos is powered by humanity's existence. So the easiest way to destroy Chaos is to kill all humans, thus Chaos will become powerless and humanity is sav... wait, what!?
    • We can also take another view and just assume that a Traitor Space Marine Legion in such a universe would probably be evil. As such, let's review old school Alpha Legion doctrine. They are not sneaky guys, that's the shtick of Night Lords and Raven Guard.note  They are not hiding behind the wall of brainwashed meat shields, that's how Word Bearers roll. What they do is essentially turning every single rank and file Astartes into grimdark Nick Fury/James Bond with heavy Rico Rodriguez influence on supersoldier steroids with mandatory power armor and 30mm automatic gyrojet rpgs. Despite that they often don't know what other nearby group of Alpha Legion is planning, each of them makes their best effort to ensure untold mayhem, civilian unrest, riots, infighting, unintended friendly fire, intended friendly fire, command chain and supply route disruption and myriads of other agendas and plans, each more complex than the previous one.note  The result of full scale Alpha Legion assault is an utterly devastated world with no sign of law and order remaining.note  The Night of the Thousand Rebellions at the end of M41 has shown that while some groups did fell to Chaos completely, becoming mindless berserkers, quite a significant portion of them remained loyal to the teachings of their Primarchs. They couldn't be stopped by Roboute Guilliman with the entire might of the Ultramarines legion (the most numerous SM legion) on Eskrador. What can possibly hope to stop them now?
      • Speaking of that day, Guilliman engaging and seemingly killing Alpharius in single combat hoping it would lead to a Decapitated Army, only for the Alpha Legion to continue curbstomping his legion with no negative impact whatsoever? The Alpha Legion didn't give a shit about the death of their Primarch. Guilliman learned that day why their symbol is a hydra...
    • The really scary thing about the Alpha Legion is just the fact that they. Are. Everywhere. Let's talk the Night of the Thousand Rebellions: they made the entire Segmentum Pacificus (that's roughly 15% of the whole Imperium) secede by launching cultist uprisings across hundreds of thousands of worlds which all occured simultaneously. Even the Lions Defiant Space Marines found themselves battling Alpha Legion forces on their own homeworld. The Alpha Legion are also the people who hypno-brainwash the natives of Astartes recruiting worlds and then trigger the unwitting recruits to turn on their own brethren just in time for an attack on their fortress-monastery. Oh, and they also have a nasty tactic of directly infiltrating loyalist chapters and using Imperial battle cries to throw Imperial forces off. Just how do you fight an army that operates like this!?
    • Just how resourceful the guys are? They waged a terror campaign that made Orks flee in panic, right at the guns of another Legion's fleet.
    • Even worse is that even the Ordo Hereticus have a difficult time fighting the Alpha Legion, as the latter will gladly subvert, delay or foil just about any conspiracy made against them. Small wonder why the Inquisition has a very special hatred for these guys.
  • You know what's really freaky? So many named characters of the Chaos Space Marines were around during the Horus Heresy. Which means the Emperor built his Empire with these psychopaths, many of whom willingly sold themselves to Chaos. The Emperor, humanity's greatest hope and salvation, was an incredibly Horrible Judge of Character.
    • Another, not exactly more reassuring, theory is that he was, in fact an incredibly good judge of character (of course, character seems to have had little to do with it, considering they were created to lead, not raised to). He surrounded himself with humanity's best and brightest. And it still wasn't good enough.
      • The problem isn't really that they were not good enough, the problem is, that they are actually the best. Think for a moment about the prospect of what Chaos actually is. It's a warp of whatever happens to be, as described a few paragraphs up and if what was revealed to Alpharius and Omegon is even only remotely close to the truth (and not another trick and treat by Tzeentch) and the happenings within this world pretty much back this claim up. Your only way of getting rid of Chaos is to simply not exist at all. As long as people are fighting for their life, there will be Khorne. As long as people want a better life, there will be Slaanesh. As long as people lay out plans to do things, there will be Tzeentch. As long as there is creation, there is Malal. As long as really anything is alive, there will be Nurgle. The harder you fight, the more you wish for a better tomorrow, the more you cling to your very survival, the more walls you raise to defend you, the more elaborate your plan on how to achieve all of this is, the more powerful Chaos becomes and by ever increasing your effort, you work in exactly the wrong direction and so it happened with the Primarchs. The worst part is, the Emperor may not even have had any choice not do this considering the ticking doom counter of Orks rolling over everyone after hitting critical mass and various other threats rising after the Age of Strife. He took the least bad option, that of giving the Great Enemy powerful monsters to plague reality with for eternity, never letting them truly win as that would reduce the fun.

    Helbrutes and other living-death machines 
  • Aptly named Helbrutes are the Dreadnoughts of Chaos Space Marines, and, much like their Imperial counterparts, they contain the broken body of a mortally-wounded Space Marine inside a sarcophagus deep inside a gigantic fighting robot. However, whereas the loyalist dreadnought is a venerable and venerated aged warrior, a Chaos Space Marine is a demon-possessed super-soldier with insatiable bloodlust. And while the sarcophagus of a loyalist is a small but not painful place to be, the inside of a Helbrute is described as more a nightmarish maw. Imagine losing all your limbs, then being shoved inside a rusty box half full of wires, half full of tentacles and probing mouths. Next, the protrusions slowly and agonizingly force themselves through your skin and muscle until they hit nerves, whereupon they begin fusing with you. Connected to a massive Warp-tainted monstrosity but completely trapped within a cramped, writhing box, the Marine within almost invariably goes insane, if not immediately from the unending agony then certainly when their flesh begins growing into the metal of the daemonic machine. The result is a crazed, nigh-uncontrollable monster that seeks only to vent its suffering onto any victim that crosses its path. Small wonder the Chaos Marines use them as a tool of punishment.
    "No. No! Not the sarcophagus... Khorne damn you, you disloyal curs, just kill me. JUST KILL ME!"
    • Also, Defilers. Huge metal spiders made from the technology of Dreadnoughts. Powered and piloted by a demon summoned by dissecting a Space Marine alive. Enjoys ripping people in half. The pilot's hatch itself is chained over, because not even its own side wants it to get out.
    • There is a short story collection called Into the Maelstrom. In short, a Space Marine Librarian (pysker) is placed undercover into the titular Maelstrom, the flagship of a Chaos Lord to find out where the lord will attack next. After he is finally given the information, he reaches out and informs the friendly troops of where the attack will be. At that point, he is captured, told that his information is fake, and he's just signed the death warrants of a dozen planets and billions upon billions of humans. After he gets knocked out he wakes up cloaked in darkness. Tubes running through his body. He tries to reach out with his psychic powers, only to find them blocked. He then realises that he's been hooked up to a dreadnought sarcophagus, which hasn't been attached to one of the machines. The sarcophagus can keep a person alive for near-eternity, and never has to be hooked up to an actual dreadnought machine.
  • When not in battle, the occupant of a Helbrute has to be chained to a wall because millennia of this confinement has driven him completely insane. The Dreadnought itself is chained to a different wall. Which would indicate that Chaos Dreadnoughts will go berserk without their pilots.
  • And on another Chaos note, Obliterators. Basically, think of a Chaos Space Marine Terminator combined with a Dreadnought and the Tetsuo Virus. These guys are Chaos Marines infected with a virus from the Warp (a daemon microbe), turning them into a hulking, bloated fusion of flesh, metal, guns and limitless ammunition. They are also stark-raving mental, to the surprise of no one.
    • They were originally Traitor Legion's Techmarines (so, some bionics already), but years in the warp and "blessings" by the dark gods caused the Obliterator virus to appear. Someone actually wrote an account of a Techmarine slowly turning into the monstrosity that is an Obliterator - in very slow and agonising detail. For example - Techmarines have various plugs and sockets in their flesh (mainly hands and head - that they feel all the time) so they can 'communicate' with machines - well, the virus caused the weapons to spawn from these. Very small holes, the size of a coin - having HUGE anti-tank missile launchers, or heavy machine guns, several times the size of the plugs, being pushed out. Veeery slowly.
  • Think Obliterators are bad? They've got a close combat equivalent now, called Mutilators. Imagine the same nightmarish shifting morass of flesh and metal fixated on melee combat, constantly reshaping itself into newer implements to slash, stab, skewer, maul, mangle, and mutilate. Worse, Mutilators chose this state; they deliberately hunt down "weapon spirits" in the Warp and devour them, absorbing them into their bodies to become what they are now. So, in comparison to Obliterators, Mutilators are technically sane.
  • Raptors are what became of Assault Marines; they're particularly associated with the Night Legion. And they get worse, too; Raptors eventually devolve into Warp Talons, monsters that live only to hunt - and how do they hunt? They use their Absurdly Sharp Blades to cut portals into the Warp so they can fly through Hell and pop out anywhere they sense battle.
    • That's not even the worse of it, Warp Talons are usually hired to assassinate certain key enemies, how do they find them? The employer gives them an item precious to the target (a locket, a watch, their old favorite toy, their mother's index finger), and the Hell Talons use that to teleport directly to their target. In other words, it doesn't matter where you run, where you hide, the Hell Talons will literally tear through another dimension to get to you. Yes, their claws are sharp enough to cut reality.
  • Heldrakes. Any Space Marine pilot that is too exposed to the Warp and too attached to his aircraft will end up becoming one with their vehicle. Literally. Until they're able to "see" through its sensors and "speak" through its vox systems. Eventually, these mutations get worse and worse and worse until all that remains is a warpfire-breathing, biomechanical dragon with its pilot reduced to a withered, fetal husk as a living battery, endlessly screaming in agony.
  • One particularly awful example of a Chaos-oriented weapon is the anathame. This weapon can "recognize" a designated target, thus tailoring itself specifically to be lethal to that target. While it was not originally forged by Chaos, it was used by members of the Emperor's Children and Word Bearers, and it was also instrumental in Horus' Start of Darkness.
  • What's the worst, darkest, most horrific part of 40k lore, you ask? One word: Daemonculaba. Warsmith Honsou of the Iron Warriors legion needed a fast, efficient means to produce more Heretic Astartes for his plans of conquest. The solution? (MAJOR squick warning) Caging female slaves, fattening them beyond recognition and implanting live human children into their mutated wombs until they're either reborn as a skinless Chaos marine or as a horrific mutant known as an Unfleshed. The newborn marine's skin would be provided by having the Daemonculaba sucked dry of all fat until they wore a "coat" of their own super-stretched skin before being flayed alive to "clothe" the newborn marine. There's a very, very good reason why the fanbase does not like to talk about this bit of lore.
    • Much to the relief of the Imperium and to 40k fans, the Daemonculaba were destroyed once and for all by the Ultramarine Uriel Ventris as part of his death-oath to restore his honor - alongside a group of renegade Astartes, stranded Imperial Guardsmen and the mutants produced by the process who, despite their nature and origins, adored the Emperor of Mankind.

    Dark Mechanicum 
  • Every little crazed Mad Scientist trope that comes to mind? The Dark Mechanicum are this and oh so much worse as they combine their knowledge of technology with Chaos and even occasionally Xenos devices.
  • The 5th Edition Chaos Codex added Daemon Engines, created in the Chaos equivalent of the Imperium's Forge Worlds by twisted tech-priests who are so buddy-buddy with daemons that the things will volunteer to be implanted in one. Essentially a colossal chunk of metal, human flesh, and the odd daemon or five jammed together in the shape of a hideous beast, they have no other goal than to hunt down and crush everything they can find. Examples include:
    • Forge Fiends have potentially limitless ammo— which doesn't sound too bad, right? However, the means in which they create the ammo is the horrifying part. The Forgefiends literally devour anything on the battlefield, from metal to corpses, in order to gain resources for their mechanical intestines to use to create more warp powered shells.
    • The Warp Smith (the one who creates the monsters in the first place) has this to say about them: "Shackle the soul and forge the flesh. Bind the machine and butcher the rest."
  • Vashtorr the Arkifane: A Daemon born from the desire to innovate and experiment, a creature of pure intellect without any ethics and/or morals. He’s so powerful, that he’s classified as a Chaos demigod in his own right, beholden to none of the Ruinous Powers. He looks like a horrible mish-mash of technology and flesh clutching a mighty hammer, with a rusted speaker for a mouth and two wickedly sharp bladed wings. He speaks with a distorted chorus of soundbites, and is described as first appearing in our realm as a cloud of pollutants, before shaping himself a body out of sacrificed tributes of flesh and technology. He’s described as a sort of arms dealer in the Great Game, supplying the Archenemies of Mankind with powerful weapons, which makes him so valuable that none of the Forces of Chaos dare kill or injure him for fear of the disadvantage that if would put them at. Recently, he’s grown a little complacent in his position, and now seeks to BECOME A CHAOS GOD IN HIS OWN RIGHT. He’s also struck a deal with Abaddon, giving him the power to reanimate Space Hulks into the terrifying Balefleets of the Arks of Omen, giving him an essentially ready-made fleet of warships which he can use to destroy the Imperium.

The Imperium

    The Emperor and Primarchs 
  • Of course the Emperor himself counts, when you look at him from a right angle. An obscenely powerful master manipulator, with enough scientific know-how to create Space Marines, who manipulated history in ways Man Was Not Meant to Know, and founded the most brutal regime in human history, founded on equally brutal conquest and xenocide. John Grammaticus once saw the Emperor's true self and got freaked out by thinking about it two hundred years ago after the incident. And let's just add that despite wanting the best for humanity, he didn't shy from sending his armies on human planets that didn't want to join. Warhammer 40k: Such a Crapsack World that Literally Space Hitler is one of the good guys.
  • A particularly horrifying theory which appears in Horus Heresy novels is that the Emperor saw the Horus Heresy as inevitable and manipulated events so that what happened in the end was the best case scenario. Try not to imagine what this implies about both the Emperor and the Horus Heresy.
    • The Emperor may be the benevolent protector of Mankind, but that's poor consolation to any one of the one thousand psykers per day sacrificed to sustain his Golden Throne and the Astronomican Beacon. Even less so when you consider that we know exactly what happens to them. They spend their time in the queue, typically months or even years, in a relatively high state of comfort. They are fed well, treated with respect, offered privacy. There is no screaming, no death threats, in fact no threats at all because most of them are happy to be there. Then the anointed day comes, a pod has opened and their time is up. With great ritual they are led from their private chamber to the pod, and Inserted. Cybernetic implants drill themselves into flesh, bone and brain within moments. Tubes are inserted to make sure they are fed nutrients and stimulants to stay alive and conscious as long as possible. Then the unfathomable agony begins. The Emperor provides the focus for the Astronomican, but has no power, being mostly dead, so his power is drained from the very life-forces of several thousand psykers, and the next month or so of their lives is utter torment as they act as biological electric batteries. It's implied that when they can no longer give any more and die, roughly a month or two later, there's no clean up because their body is ultimately disintegrated in the process. And the reason they look forward to this ungodly existence? Because the alternative is a LONGER lifetime of pain, madness, daemonic corruption and ultimate violent death, typically to little or no benefit to the Imperium as a whole.
  • Two things that came out in the Eighth Edition that will cause a Mass "Oh, Crap!" moment for any player opposed to Chaos. The Astronomican is going out. AND THE GOLDEN THRONE IS FAILING.
  • The early days of the Primarchs, if you look at it from the Emperor's point of view. So you have your children in a nice safe place, right? Turns out the place isn't safe enough and your kids just ended up in the Warp kidnapped by four Space Horrors that really don't like you. Have a nice time imagining what can happen to them. At least when he found them they were all total badasses and even so, when he found them, they weren't all as expected. Imagine rediscovering your children after decades, maybe centuries of not knowing what happened to them, to find that they've been altered by chaos, one a cyclops, one winged. Chaos gets to everyone.
  • Since we're here, why not the Emperor's point of view now? Being hooked up to a life-support machine for ten thousand years, neither alive nor wholly dead and apparently still conscious? Definitely an And I Must Scream scenario. And consider the following. While ensconced upon the throne for ten thousand years, you have been lovingly and happily told what's been going on. Everything you worked for has been turned around, every word you have said taken out of context and re-imagined to fit the ends of the new religion that holds you as god, the same religion you tried to stamp out. Everything you wanted—enlightenment, negotiations with the rare peaceable Xenos race, the pursuit of technology to better humanity, equality and peace through a unified power structure with built in oversight? Are considered insane or evil and can get people the death penalty. Consider everything wrong with the Imperium of Man - IT IS ALL DONE IN YOUR NAME, FOR YOU, AND WITH YOUR 'BLESSING'. As one person put it, "The only sane man in the universe can do nothing but watch everything go to Hell." Then there are those who suspect that this was part of the Emperor's plan all along.
  • Two of the original 20 Primarchs are completely unknown; all records of them have been wiped out by Imperial decree. People tend to assume that, for the two missing primarchs and their legions to be completely un-personed, their crimes must have been a thousand times more horrible than those committed by Horus and co. A far simpler -and more likely- explanation is that the whole thing happened during the Great Crusade, when the Imperium was strong and the Emperor in full control, so it was possible to erase every record of the events.
    • Seeing as the Emperor purged all the records about his sons (and most likely ordered their execution) even while most other primarchs were clearly disturbed about it, just what sort of tyrant was he for other, less valuable subjects of his?
    • The Chamber at the End of Memory gives a few clues as to what happened to them. Namely that the actions resulting in their 'loss' were enough that the other active Primarchs consented to letting Malcador modify their memories and prevent the two from being remembered, and that their loss "threatened the ideals at the heart of the Great Crusade." The biggest comes at the very end, from Dorn's briefly unsealed memories of them - that if the two missing Primarchs were still with them, the Horus Heresy would already have been lost. This had led to speculation that whatever they did was somehow an existential threat to the Imperium and/or the Emperor's goals.
  • Though the Emperor is usually represented as a huge Jerkass and Tautological Templar unable to relate to his sons and humanity in general (Lorgar, Angron, The Last Temple story, other stuff), there are enough hints to imply that it is not so. Judging by his treatment of Kai Zulane in Outcast Dead, and some other people, including his sons (Vulkan, for example), it's highly likely that he perfectly understands them. Add his precognitive powers and knowledge of his death, and the possibility that he had known about it before Kai told him, we can conclude the Emperor knew about Horus Heresy, led to it, and that was the best way. In short, the Galaxy in 40000 is the best of other variants.
    • Or he is not. Which is even worse.
  • The Emperor's Webway project. The plan was to use the psychic power of the Emperor to dig a hole in reality leading to the Eldar Webway, while simultaneously fortifying it against Daemons. This eventually proved to be too draining even for the Emperor's enormous power when he had to leave the Great Crusade and take his place on a psychic amplifier, the Golden Throne. Then Magnus happened and crushed the barriers in the human webway tunnel leading to a massive demonic invasion in the Palace of Terra. Novels hint that this resulted in an instability in the original "hole in reality" thingy and now it drains more psychic power then ever to keep the rift from turning into a new galaxy wide Eye of Terror. There is also a scene in a novel, long after Magnus's betrayal that features a series of Emperor Titan-sized adamantium doors deep within the Palace of Terra. Even when standing at the first door it sounds like the greatest battle of all time was going on behind them. What it means is the breach was not sealed, the demonic incursion on the holy soil of Terra is still under way, and the Adeptus Custodes and Sisters of Silence constantly have to keep Daemons from overrunning the heart of the Imperium and shutting off the Astronomicon. We do know that the daemons weren't able to break into Imperial Palace again, but they destroyed a lot of irreplaceable pieces of ancient machinery, tied up some of the most capable and valuable forces of the Imperium— and there is not a single reason for them to stop trying. Daemons can not be killed. Every victory is but a delay, every Custodes is irreplaceable. Oh, and the psychic strain is so devastating that there is no hope for the Emperor to recover any time soon and the Golden Throne is failing. But we knew this already.
  • There are many hints that the Emperor of Mankind has, over ten thousand years, become something more than he was when he first was interred in the Golden Throne. In other words, the Emperor might truly have become the God-Emperor, and that is not a good thing.
    • Throughout the book The End and the Death: Part 1, mention is made repeatedly of a “Dark King”, implied to be the gestating essence of a FIFTH CHAOS GOD. We are led to believe this is Horus until the end of the book. As the Horus Heresy comes to a close, and Horus’ soul is destroyed, all four Chaos Gods start laughing and chanting the Dark King’s name. The next line puts the entire setting in a different context...
    • Even near the end of the Horus Heresy, it’s heavily implied that the Emperor was undergoing apotheosis, becoming just like the soul-hungry Chaos Gods He fought against, drinking Malcador’s energy until there’s almost nothing left.
      The young man holds the waterskin up again, but this time to the man’s mouth. A trickle flows at first, then a little more. The man beneath the tree drinks and drinks, slowly at first and then insistently, glugging and gurgling the water down. The young man takes the skin away when there is just a mouthful swashing in the bottom. The man beneath the tree looks up at him, and His eyes are dark holes and there is nothing kind in the grasp that grips the young man’s arm.
      ‘I must keep something,’ says Malcador, re-stoppering the skin and hanging it over his shoulder. ‘For the journey back.’
      The man beneath the tree, who here is far from an Emperor and too close to a god, nods, then slowly releases His grip.
  • The Ordo Sinister, better known as the Emperor's personal Titan legion. Their Titans work by surgically bonding a dozen or more Alpha-class psykers to it then painfully draining their life force to power occult weaponry; the Princeps has to be a psychic null or be ripped apart by the sheer amount of agonised psychic screaming that results. Oh, and it's very heavily implied that their weapons are capable of outright destroying souls.

    Space Marines 
  • The Space Marines themselves are incredibly disturbing after reading an in-depth description of the process used to create them - almost twenty extra organs (over twenty if he's a Primaris) getting surgically stuffed inside them? And eventually getting turned into an inhuman killing machine completely subservient to the military. But the thing that really gets to people is the sheer hypocrisy (intentional on GW's part, we're sure) of creating these Super-Super Soldiers to destroy anything not human, yet they're so completely altered in mind and body that they're no longer human at all.
  • In Graham McNeill's Warriors of Ultramar, Uriel Ventris of the Ultramarines compares his life with that of a Planetary Defence Force trooper whose life he saved, deciding that the sacrifice he made by becoming a Space Marine and sacrificing a large part of his humanity was worth it because he was given the chance to be part of something greater - defending humanity from a hostile universe. Chaos Space Marines, on the other hand, often decide that the loss of their humanity was well worth the power they gain from being a genetically-engineered killing machine.
    • An Imperial Guard officer comments on this in Bleeding Chalice when his troops start to feel better because the Imperial Fists chapter have come to save them: "Do you know how they make Space Marines? They take teenagers, right when they're at that age when you think you're invincible and nothing can kill you, and they give you a gun and armor and send you out to kill in the Emperor's name. If you ask me, they're scarier than the aliens."
    • Marines are 7 foot tall, peerless superhuman warriors that spit acid, have bulletproof chests and make Master Chief look like a paintball player, and that's before they put on their power armour and pick up their "holy" bolters. To be selected, you must be one of the finest warriors from a planet where life is so brutal that surviving to be a teenager is an accomplishment (either a Hive World, a Feral World, or a Medieval World) and prove your worth by slaying the local dragon-xenos or in the fires of war. Before puberty. You then undergo training that makes other 40k regimes look soft, filled with brainwashing and worse. You're stuffed with extra organs, including one which alters your genes, rendering you sterile but allowing you to be bigger, stronger, faster, and (hopefully) survive the extra heart they need to grow. Only the toughest achieve this much. Then you get scout armour, and have a trial by fire (which, in the 40k universe, is more like trial by throwing-you-into-the-sun anywhere else). Only then are you accepted as a full marine. Marines are fanatically devoted to their proto-clone and the Emperor and answer to no one alive save their chapter master. They are capable of cleansing a planet on a whim, and more than ready to if they think their pride/honour has been besmirched. And they're touchy. They are portrayed as demigod-like angels of death in Imperial propaganda. Add in a touch of medieval knighthood, chapter-specific influences and even more grimdark and we have a Space Marine. Then things get worse.
    • The brutal genetic and surgical regime undergone by an aspirant space marine is best commenced before the age of 12, with most begun at 10 years old. The one personality requirement is a natural killing instinct. Repeat that: an ideal space marine should display a killing instinct by the age of ten.
      • It's strongly insinuated that some of these organs are implanted while they're still conscious.
    • Variants include the chaos daemonic version, the INSANELY heavily armed & armored version (as if their rapid-firing RPG wasn't enough, along with their RPG pistol sidearm), the Viking berserk werewolf version, the fire-crazy dragon-born version, the cyborg version that prays to the god-machine and tends to the souls of vehicles whilst applying nuclear welders to opponents, the bishonen vampire version that hides their bloodlust & berserker rage underneath their seriously beautiful faces and more.
    • Speaking of the Viking Berserker Werewolves, (The Space Wolves, or Vlka Fenryka, due to an in-universe "Blind Idiot" Translation) they're some of the most genuinely heroic characters in the Imperium, something that almost makes you think they're not too bad. But like many chapters, they have their own brands of nightmare fuel.
      • Like the Blood Angels (more on them later) they have their own kind of terrifying insanity: That of the wulfen, in which the wolf in their gene-seed overwhelms them, turning them into werewolves for all intents and purposes.
      • Those giant fuckoff car-sized wolves they ride? Those are also werewolves, strangely enough-the descendants of colonists who used the DNA of arctic wolves to make sure that they could survive on the horrible Death World that is Fenris. But that went either horribly wrong or horribly right, depending on how you think of it, and the colonists somehow mutated into lupine monstrosities.
    • Starting in the second book of the Blood Raven's trilogy, the process of making a regular man a Space Marine is actually detailed. Stuck in restraints in a room filled with disease, you are cut open, have new organs shoved in, have your eyes cut out and replaced, have your brain burrowed into and 'fixed', and a number of other horrors inflicted upon you. Oh, and they don't bother patching you up, mostly to test if you're really strong enough. And in addition, you're not given any anesthesia, as it would interfere with the implants bonding to you.
    • Luckily, unless you're trying to hurt them, you don't need to fear the scariest of the good guys - the Space Wolves, who are badass Vikings with fangs, eternally crusading and the Soul Drinkers, who are mutated rebels but not evil ones. The Blood Angels, on the other hand, just hope they haven't given in to the Red Thirst & the Black Rage.
      • Not to mention the fact that they have a tendency to go complete batshit nuts just before a battle, to the point that they consider having half their bodies blown off nothing more than a flesh wound. Oh, there's also the fact that if they don't have a Chaplain to rein them in they might just start drinking your blood from your still-beating heart.
      • Why do you think they're so noble? They try their hardest to be, to avoid losing their minds and reliving the last memories of their Primarch before he died. They are powerful and loyal allies once on your side, but heaven help you if they're not.
      • Whether or not they're on your side isn't quite the guarantee of safety you'd hope for. The Sisters of Battle once fought alongside the Flesh Tearers and local human militia against the orks. The Sisters and militia were surrounded, but the Flesh Tearers fought their way through the orks, annihilating them, and didn't stop. They slaughtered the militia in their frenzy, and the Sisters of Battle retreated rather than fight them.
      • The battle of Gaius Point is horrific for the Flesh Tearers themselves. It was supposed to be a glorious victory that saved the township and restored their honour; instead, because of the Black Rage (something they're affected by worse than any of the other Blood Angels-descended Chapters), it's a dishonour they can't erase and that's turned their allies against them. And nobody would believe them (or care) if they tried to explain, including their fellow Sons of Sanguinius.
    • Black Templars once encountered an incredibly powerful psyonic Xeno. After killing him they learned that resulting psychic backlash resulted in deaths of hundreds of billions Imperial citizens. No one present even questioned if there was even a remote possibility to resolve the matters differently.
    • Oh, and remember that bit about the Tyranid Lictors? The bit about them eating your brain to take your memories? Yeah, the Marines do that too.
    • There is a rather large Chapter of Space Marines that have a secret so Dark that these particular Angels of Death will actively avoid Inquisitors and only a handful top tier of the inner circle know even a portion of whatever truth caused them to change their chapter colors and live in shame. A Space Marine that is above morality and emotions living in shame for whatever happened in the Chapter's past. What could have possibly happened to this Chapter?
    • One short story shed some light on much debated purity of the Grey Knights chapter. Those psybolts shells that are so effective against daemons? Every single one of them of them is imbued with a life force of an righteous man. Those wonderful Aegis power armor suites? About a dozen of psykers each. Infamous Khornate Knights story?note  Pretty regular occurrence.
      • The good part? All of of those good people sacrifice their lives willingly. They follow the Imperial Cult, the religion created around being the martyr for the sake of Imperium. Oh, wait, that's the bad part. And yet they still must. That's how bad their universe is.
    • There is something deeply disturbing about certain loyalist chapters. Let's take one example, the Charcharodons. These guys appeared out of nowhere during the Badab War. They sought out the Inquisitor in charge, offered their service in High Latin, then... did so. They deliberately target civilian populations to force the separatists to defend them. They fight in complete silence while using close quarters weapons and infiltration to cause maximum panic. On the way out? They take the children of their surrendered foes and force them to fight to the death to replenish their numbers. It's implied this is pretty normal for them.
      • Other disturbing loyalists include the Exorcists, who force daemons to possess their recruits, executing them if they fail to force the Daemon out with sheer willpower, the Minotaurs, who are implied to be an execution force against other loyalist marines and the Marines Malevolent, who have absolutely no regard whatsoever for collateral damage, consider civilians less than useless and whose defining moment in the lore was bombing a refugee camp with heavy artillery after an Ork warband got inside the camp's perimeter. Their heavy handed tactics ensured the Ork warband was utterly destroyed and so the Marines Malevolent consider it a resounding success, completely disregarding the little matter that their actions caused civilian casualties in the tens of thousands. It's telling their brutality has caused many other Space Marines Chapters to either refuse to fight alongside them, or at the very least demand the Inquisition enact some form of penal action against them.
  • Dreadnoughts. A super-soldier is so horribly wounded the only way to save him is to seal him in a life-support sarcophagus. From then on, his entire existence is either sleeping in a deathless trance or rampaging around the battlefield in a walking tank.
    • There's more: the link between the entombed marine and the dreadnought is FAR from perfect and doesn't override input from the mangled body inside. Aiming that nifty assault cannon? The shredded stump of an arm is dragging along the inside of the sarcophagus doing the same motion. Opened your mouth to speak? People may hear a deep, fearsome robotic voice, but inside you're swallowing gallons of freezing, revolting amniotic fluid, and you feel all of it. Forever.

    Imperial Guard 
  • Now that you've read all this, imagine being an Imperial Guardsman. That is to say, a normal person armed only with a laser rifle, a flak jacket which you will quickly discover to be almost useless, and training not much different from the modern military and say the entire Warhammer 40k universe isn't out to get you. It doesn't help that military propaganda says every guardsman is expendable.
  • On a similar note: Battlefleet Gothic features ships kilometers long, with torpedo bays. Torpedo bays with three hundred meter torpedoes designed to scream across space and cripple a kilometer-long spaceship. And the Imperium loads these things by hand - by chain and pulley. Not because they couldn't do it automatically, but because it is easier to enslave a thousand humans than it is to build loading rails. The Imperium's greatest resource is men: "Give me enough of them and I shall choke up the Eye of Terror."
    • It is often said that the Imperium only has one abundant resource (and they have rechargable solar-powered guns mind you) and that resource is literally human bodies.
  • The entire reason why Deathworlds and Hiveworlds work in Warhammer 40k; they export bodies in exchange for supplies. Deathworlds often are recruited into Space Marine Legions or are required to raise Imperial Guard regiments. Hive not think about what they do with the bodies.
  • Oh, and, hey, Guardsman, you know that gargantuan, ravening daemon you just took down, staring seething madness in the face as you stood firm against its foul emanations? Are you imagining medals and a kegger? Well, unfortunately, you were fighting alongside the Imperium's top daemon hunters, the Grey Knights. Of course you didn't know this because they keep their existence secret, and will continue to do so by executing you and your entire regiment. So sorry.
  • Now imagine being a member of the PDF, who are the people used to buy time for the Guard. The Red Shirt Army for the Red Shirt Army. Not only are you screwed, you don't even have enough training to reduce your degree of screwedness.
    • Note that PDF isn't just a bunch of incompetent fools. This is a regular army of a normal society of the 40k. They train hard, they have competent officers, their equipment is mostly the same as in the Imperial Guardnote . They have the very same body armor, lasguns, heavy weapons teams, artillery, tanks, aviation and space fleet. It is the best their world has to offer to protect itself. It's just not enough. It's not even close to be enough.
    • Though some PDF, mainly from wealthy and/or important worlds (especially Forge Worlds), can be as well or even better equipped and trained than the Imperial Guard. Still, though, most Forge Worlds have permanent, massive IG garrisons, not to mention the Adeptus Mechanicus' legions of cybernetically enhanced warriors (who are far more capable than the IG, or should be; they're not dealt with much in the fluff and even less so in the crunch)note . Some worlds, though, have a massive industrial complexes which are extremely important, and with production schedules stretching ahead decades, but don't necessarily make the worlds they sit on Forge Worlds, nor important enough for a permanent IG presence. These are the worlds that tend to have excellent PDF's, simply because they can manufacture lots of top-tier (by human standards) equipment. Wealthy worlds, those with large noble populations or extremely lucrative trading or corporate worlds generally have enough money just to pay for very high quality PDF's.
  • The amount of horror varies depending on who you're fighting. You can pretty much expect Orks to just kill you. Tyranids will usually just eat you. Eldar generally just kill you if you're in their way (whether killed by their hand or by the hand of another faction they influenced to attack you). Tau might even take you prisoner without doing horrible things to you; hell, you might even get to join their club if you don't mind being a second-class citizen and never seeing the Imperium again, because if you do, they'll brutally slaughter you as a race traitor. Simply being shot/eviscerated/turned into a pile of shredded flesh isn't really so bad considering what would happen to you if some of your foes feel like taking prisoners, especially the Dark Eldar. You do NOT want to be captured by the Dark Eldar.
  • Note that a lasgun is considered to be, more or less, a slightly better modern day assault rifle. A flak vest is considered to be roughly the same as combat armour worn by most modern day advanced troops. In fact, it might even be said that it's better since it's stated that they're capable of withstanding light machinegun fire, which is already way better than the bulletproof vests that modern forces use (that only reliably stop pistols and shotguns). They are literally the best of our troops transplanted into the Horizon-line-dancing, cosmic wedgied universe that is 40k. And they die in droves.
    • It should be noted that the Lasgun is many time stated to be able to completely destoy a slab of cement with a single shot. By modern standards, it would be the equivalent of shooting with an automatic, recoil-less, 50. anti-armor rifle with unlimited ammunition. By W40K standards, it is little better than a flashlight. One of the weakest, puniest, most easily mass-produced weapons of the Imperium which can be used as expendable hand-grenades by imperial guardsmen in times of need, could destroy a modern battle tank in a single shot. This gives you some insight into the sheer strength, toughness and resilience of what these common men have to face doesn't it?
  • Much of the Imperial Guard also turn Traitor, usually at the lure of grandeur or daemonhood. However most turn to worship of the Chaos Gods simply to escape living under Imperial rule. In this universe, making a deal with the literal devil is an actual appealing choice over military service.
    • Yet if you make a deal, since we are talking about Chaos, you will regret it. FOREVER.
      • As noted on the Headscratchers page, sometimes the average Guardsman doesn't even realize his regiment has turned to Chaos.
  • That's not to say the horrors are confined planetside. The great space fleets have their own worries, on top of the ones that we already know about space travel. Just to start, space hulks. Lumbering conglomerations of asteroids and ships that may or may not be infested by xenos/demons/things too horrible to imagine. Oh, and since they can also contain priceless technology, there are always plenty of volunteers to board it and look around. And did we mention that these things (Space Hulks) are bound to a) Contain Orks, b) Chaotic Evil Superhuman Soldiers and their demonic friends c) be the bastard child of Event Horizon, Aliens, Dead Space, and every other movie where a crew goes on a ship and things get bad fast, d) Something Worse, or e) All Of The Above?
  • And in addition, even if you, as a bog-standard Imperial Guardsman, actually survive to your honorable discharge, the best you can hope for is being allowed to settle down on the world you just helped to conquer/save. As soon as you are recruited into the Guard, chances are you'll never see your homeworld ever again.
  • A short list of crimes in the Guard you can be executed for include: Mutiny, compromising comms security, murder of compliant citizens, and finally- neglect or ill-use of accoutrements. Yep, you can be executed for failing to hang up your spare uniform correctly. The book this is listed in also explicitely states that you are expendable, that you cannot leave your barracks during a warp jump, and has a section of "Sanctioned Psykers" that has been taped over another, worse section where the only words visible are "Exterminate without mercy or quarter."

    Imperial Inquisition 
  • Warhammer 40000 has its own subsection in the quotes page for Church Militant, and it's not hard to see why. The Inquisition has the power to turn all the biomatter on your planet into flammable goop with a word (aka. Exterminatus), command assassins that include psychotic murder machines that explode on death or ones that fire bolts of pure anti-soul, and countless other horrible ways to kill or torture anyone who catches their attention.
  • Or the people who don't. Exterminatus has been ordered just to be sure on more than a few occasions, with any notable people taken off planet for Inquistorial interrogation.
  • The Life Eater virus is a form of Exterminatus which reduces all life, from the largest animal, to the smallest flower, to a rotten sludge, which is ignited with one blast of a superlaser, burning away everything on the planet, even the atmosphere. It has generally fallen out of favor, since it seems to bolster the forces of Nurgle.
  • Fortunately for every non-human in existence, the Inquisitors spend far too much of their time engaged in their own philosophical squabbles, demonstrating that near-infinite resources plus no supervision plus being actively encouraged to think of yourself as the divine will of the Emperor is perhaps not the best combination.
  • The Witch Hunters have access to a device known as the "Excruciators". This grants the Witch Hunters player 1D6x10 bonus victory points, as he horrifically tortures an enemy with them.
  • The Inquisition are one of the highest levels of horror. A regular human will fight because he is told to. Humans don't think about what they are doing, they just do. This applies even to Planetary Governors, Space Marines, Starship Captains and so on. The Inquisition not only have to think for themselves, they have to understand what they are fighting, why it needs to be fought, and worst of all, to know and understand the consequences of the actions that must be taken to defeat them. Can you imagine having to learn and understand a Tyranid? Sure. It would be like understanding bugs on Earth. Imagine creating bug spray, including what it does to humans. Now, could you drop that bug spray over the entire Earth, and kill billions upon billions of people, even to save billions more? The Inquisition do. And they watch.
    • And there's a horrible side effect of this knowledge:
      • The life cycle of a Inquisitor usually starts as a Puritan full of promise and hope right out of their schola, attached to another Inquisitor and learning the ropes. They learn pretty much right from the start how the Grimdark universe actually works. Those who were vetted into the Inquisition after combat like Imperial Guard veterans and who climbed the ranks, as opposed to particularly promising youth directly picked for service, may have some idea but they can be just as rudely surprised that those scary guys with the rosettes and all the power are not living happy lives.
      • By the time they're their own Inquisitor they will be bitter Combat Pragmatists, using everything they can to win the war against the enemies and traitors of the Imperium.
      • From there, if they survive, it is a very short hop across the invisible moral line in the sand, of which there are plenty: One too many sacrifices for the good of everyone else, succumbing to the temptation of using disallowed artifacts and rituals, one too much distrust of the local population, etc.
      • These Inquisitors will then have become Radicals, still assured they're in the right due to not being able to see their gradual corruption, unable or unwilling to see how statements such as "Use Chaos against Chaos" just doesn't work.
      • Finally, these Radicals will then meet their end as traitors - usually executed by Puritans who'd, if they lived long enough, eventually become hypocrites by becoming Radical themselves. If they're "lucky" enough to be considered redeemable, odds that they'll be turned into an Arco-Flagellant or wired into a Penitent Engine to find honorable death in battle to save their souls.
    • Popular portrayals of Inquisitors show them as completely uncaring and cruel when it comes to their methods, but a few tidbits of lore hint that many of them are consciously aware of their actions and the consequences thereof, for both the population and themselves. The Inquisitor who held off Hive Fleet Leviathan was eventually stripped of his rank, branded a Radical and potentially later killed as a heretic, as well as pitted the Orks against the Tyranids knowing full well that the victor rising from the conflict will be greater than the sum of the combined might of the two armies. He knew that this would ultimately cost him his life, his reputation and the lives of millions. But his actions is implied to have saved billions by diverting the attention of Leviathan so the Imperium can regroup and form a more lasting strategy.
  • One discussion in R/40klore pointed out something unsettling about the Inquisition that makes the life of an Inquisitor almost as unsettling as that of a Space Marine's. The sheer weight of horrible things an Inquisitor sees causes what one redditor describes as "[like the] very worst sort of burnout that cops in high-crime communities experience, turning it up to eleven, and then there's no option to quit or retire, and with rejeuvenat, you can be on the job for centuries." Most of them only leave the job through death (or perhaps a Fate Worse than Death, this setting being what it is) and vanishingly few of them are able to retire in anything approaching comfort.
  • And in the truest tradition of 40k, it still gets worse. The Inquisition labels some threats not "Extremis Diabolus" (Daemonic/Chaos), "Hereticus Abomini" (heretical), or "Xenos Horrificus" (alien), but "obscuras" instead. The first example that springs to mind are the halo devices — small trinkets of unknown origin, the halo devices are indistinguishable from normal jewelry but somehow make you immortal. Wearing one will slowly start to de-age you until you're once again in the prime of your life. It then starts to sink into your flesh, and at this point you start having nightmares of eating human flesh. Your body slowly becomes stronger and tougher, healing from any wound. The third and final stage continues the process, except now you need to feed on other people to survive and your body starts to twist into something that could almost be called insectoid. Not that you'll mind, because by the third stage it just won't be you in there anymore. You're also indestructible and a single atom of ash from your corpse can revive you if it touches blood and an electrical current. And the very worst part of it? These things aren't created by any of the major players in 40k and nobody knows what they're for or where they came from. This, in a setting where Lovecraftian horrors are a known, expected and planned-for occurrence.
  • Inquisitor Kryptman's mass Exterminatus. Even the Inquisition excommunicated him for this. The worse part? Kryptman didn't do it because he was sadistic or paranoid or even zealous. He did it because he was desperate. Kryptman truly believed that it had to this to stall the Tyranids. It just goes to show how horrible being an inquisitor is.
  • Inquisitor Heldane's face is altered to look like some sort of mutant horse in order to inspire fear.
  • It gets interesting when you consider some of the Inquisitor characters. One of them is slowly being driven mad by the Eldar spirit stone he's nailed to his helmet.
  • Their method of interrogation would give Jack Bauer night terrors. They engage in nine "actions" designed to get the desired information, in increasing order of pain and suffering. The first action is simple verbal interrogation. The second is a description of the next seven actions, which get progressively more painful/invasive, until the ninth action is undertaken, involving all manner of torture performed with the sole intent of causing grievous physical and mental agony, with verbal interrogation to follow if the subject survives long enough to spit anything out. Many people break at the first action (given the Inquisition's reputation), and relatively few people persist past the second. The ninth action is simply giving the stubborn bastard a horrible, horrible death over months just to spite them for daring to not break.
  • There are four Ordos of the Inquisition whose true purpose is unknown: Desolatus, Senatorum, Necros and Thanatos. The only given details are that Necros has just five members and Desolatus consists of only one. The Senatorum can be inferred as watching the Senatorum Imperialis (the highest legislature of the Imperium and the lesser members of the High Lords of Terra, the Imperial Government) for corruption and Thanatos can be inferred to be working with regards to something related to death itself, but the Necros and Desolatus have nothing to go on as to their purpose.
    • And then there's the Ordo Vigilus. Their only job is overseeing the Ordo Necros. What happens to be important enough that an entire Ordo is dedicated purely to keeping an eye on them is never explained.
  • In sum, everything you need to know about the Inquisition is contained in its motto: "Innocence proves nothing."

    Adepta Sororitas (and Ecclesiarchy in general) 
  • Adepta Sororitas, most notably the Sisters of Battle, are usually seen as the nicer aspect of the Ecclesiarchy - at least the cooler one, particularly given Games Workshop's attempts to sex them up in recent years. But they are terrifying. Woe betide any of their number who might ponder betraying their oath; the punishments they have for traitors to their order would awe the Dark Eldar.
    • Case in point: penitent engines. If a sister or other Ecclesiarchy member has been found wanting in his or her zeal, he or she might be dragged to the darkest dungeons and tortured; after which their nerves will be hardwired into a cybernetic torment amplifier that floods their mind with so much pain that it actually powers the machine itself. Sent into a seething, screaming rage, the hapless occupant of the engine is then sent out onto the battlefield, their mind's perceptions altered so that they see every foe they drive relentlessly through has their own face.
    • And then, there are the mortifiers. If a Sister falls from the path of Repentia, a last chance at redemption achived by fighting the enemy in nothing but rags, even so much as to flee from battle, they are placed in the worst of prisons: the mortifier. A mortifier has all the benefits of a penitent engine, with added nightmare fuel. Along with pain amplifiers, metal rivets are driven into the wayward Sister's body, and a soundproof hood is placed over her head so she can never hear any words of praise, hoping to fight hard enough that they may somehow be redeemed in death. Repentia who actively betray their orders on top of showing cowardice are instead placed on Anchorites, which has all the devices of a Mortifier but placed in a coffin-like tank similar to a dreadnought. Deaf, blind, and aware only of their constant suffering they will fight over and over until they finally collapse, unleashing a final storm of devastation in realisation that their soul will soon be taken by the Warp, desperately begging for forgiveness that may or may not come.
      • Some Sisters who are mortally wounded voluntarily go into anchorites but these lack the torture devices and are revered like Dreadnoughts allowing for a veteran to fight still, but it still is no walk in the park.
  • Goge. Vandire. The guy with (as TTS put it) "the most fucking evil name I've ever heard" and cruelty to match, aptly described by 1d4chan as "If Stalin became the pope." He managed to turn the Imperium into even more of a totalitarian nightmare. The Ax-Crazy mad tyrant was able to take over both both the Administratum and Ecclesiarchy. He violently purged anyone who questioned his decisions (and often innocent people who didn't), ordered the massacre of civilian planets for the pettiest of reasons, and gleefully tortured his opponents. His Reign of Blood led to the deaths of trillions. But perhaps the most horrifying part of it all is that, during the whole thing, he had a fanatical following that carried out his orders like they were the words of God, and it took the Emperor himself to get them to wake up to their senses. Unlike most other people on this page, really disturbing about Vandire is the sense of realism. He wasn't a cacklingly sadistic and mutated Chaos worshiper, he wasn't working with aliens, he wasn't biologically modified. He was just a man capable of great evil. Unlike daemonic or xenos tyrants, Vandire is awfully reminicient of real-world dictators and cult leaders.
    • Actually, even in the 41st millenium, there is a sect called the Temple Tendency that looks at all he did and thinks he was right. Unsurprisingly, they are considered heretics by the Imperium at large.
    • Worth mentioning is what he did to Lord Phaedrus, the master of the Adeptus Astra Telepatheca (the psyker organization). Phaedrus stood in opposition to Vandire's power, so to get him out of the way, Vandire had a Culexus Assasin take him hostage and Mind Rape him to the point he was no longer a psyker. Phaedrus was driven to suicide, but Vandire made sure he didn't do it, and manipulated this depressed and mentally violated man into being his pawn.
    • One of his action is using servo-skulls and cherubs (which you can read about in the "Servitors" folder) as Sinister Surveillance all over the Imperium. As if those things weren't unnerving enough.
    • One of his norotious deeds include, after taking over the planet Boras Minor, he orders every girl under 12 years of age be taken as his slave. And GW never specifies why, leaving it up to you to fill in the blanks.
    Adeptus Mechanicus 
The Tech-Priests of the Adeptus Mechanicus are living scifi body horror. Not only do they occasionally replace half their brain with a computer to free themselves from emotions, but they're one of the most powerful forces in the Imperium. This wouldn't be so bad until you consider how many of them are horrible, horrible people - Archmagos Khobotov from Soul Drinker basically thinks "The Soul Drinkers have an ancient right to the Soulspear, since it's their holiest relic. I don't. I'm going to take it anyway." They literally do not care about anything other than the technology - no honour, no justice, definitely not other people's lives. They will gladly put an entire world's population at risk in order to have a chance to loot a Necron tomb, and tend to act offended when people wall off Necron tombs rather than letting themselves get annihilated by psychopathic robot skeletons. And they're so powerful no-one will ever be able to do anything about it. Nice or ineffectual and sympathetic versions (like Antigonus in Dark Adeptus, Felicia in Death or Glory, Ernulph and Logash in Caves of Ice, also multiple characters in Titanicus) do exist; indeed, they probably don't include a higher percentage of bastards than the Administratum. However, their really nasty members are in a position to screw over trillions of people in the name of the Omnissiah.
  • It gets better. That great machine spirit the Adeptus Mechanicus worship? Odds are its an Eldritch Abomination sleeping inside Mars, and when it wakes up it will literally eat the Sun.
  • Some say that the Void Dragon is perfectly happy where it is, because it coexists with humanity— by devouring the life-force of every techpriest in the universe through their implants, bit by bit.
  • Here's one from the Space Marine Battles novel Helsreach. Titans have a very strong machine spirit, which is constantly seeking to take control of the vehicle, and needs to be kept under control very carefully by its crew. What happens when things go wrong? The Princeps, the commander of the vehicle, gets mind-raped by a Humongous Mecha. Oh, and you now have a two hundred foot tall war machine which wants to kill everything it can see. Have fun dealing with that.
  • Ranking below the Tech-Priests of the Adeptus Mechanicus are the Skitarii, who act as the foot soldiers of the Mechanicum in a manner roughly analagous to the Imperial Guard. While your average Tech-Priest is likely to have a few augmentations, with higher-ranking Tech-Priests likely to have more, Skitarii are all heavily augmented to an individual, to the point where in some cases the only difference between them and a Servitor is that the Skitarii are allowed to retain their personalities and higher reasoning abilities (usually). Keeping their memories is optional. This does not mean that they are any more valued as thinking beings by their Tech-Priest masters, however, as all Skitarii have been fitted with neural augmentations that allows a Tech-Priest to see and hear everything an individual Skitarii does through remote data links. They can also use these links to force Skitarii to go on suicidal missions or even take over their minds and bodies completely like a remote-controlled drone. The Skitarii see this as direct communion with the Machine God and welcome it. They're terrifying to face as well, moving in unnatural, mechanical unison like an army of toy soldiers, advancing on their foe with merciless precision and unyielding calm, utilizing guns that weaponize radiation and vaporize targets with blasts of electrical energy, all while their masters watch from orbit, calmly analyzing and archiving the data every time one of these horrible weapons is fired.

    Officio Assassinorum 
The little-mentioned Oficio Assassinorum is Exactly What It Says on the Tin. They are a very secretive group that train assassins, with each sub-group or "temple" using distinct methods of assassination. The idea of the vast and powerful Imperium directing their ire at a single individual is frightening enough, but the methods used by each of the temples range from unnerving to outright horrifying:
  • The first is the Eversor Temple. They "train" Eversor assassins. The Eversor assassins are what you would get if you patterned Terminators after Viking berserkers. Literally kept in cold storage until they are needed, the Eversors are so pumped full of combat performance enhancing drugs that the first augmentation they receive is a boosted immune system just to survive the drugs in the first place. They get aimed at whatever party has offended the Imperium, then shot directly at command centers, the palaces of rogue governors or right into the thick of battle. They proceed to carve bloody, combat-drug infused swaths through the enemy in a psychotic rage, with neurotoxin-firing pistols, neurotoxin injector claws and anti-tank bombs leaving them capable of destroying anything and anyone in their path to get to whoever they are told to kill. If they survive, they get placed back into cold storage until the next assignment. If not, they explode with a blast capable of killing everyone in the room, the room and the building the room is in.
  • The second is the Culexus Temple. Culexus assassins are created from the Pariahs, people who are literally born without souls. Their mere presence drains the strength from psykers and their weaponry is specifically designed to enhance their psychic-nullifying capabilities, before getting in nice and close, then sucking out their life force. They unnerve normal people, horrify psykers with their mere presence and Eldar Warlocks consider them nothing less than the very embodiment of evil itself. They have armor to match, too.
    • It was at the hands of a Culexus assassin that the T'au Supreme Ethereal Aun'Va met his end. Aun'Va commanded the T'au, one of the most technologically advanced races in the galaxy, who obeyed his every whim with the utmost loyalty. During a campaign on a former Imperial world, the assassin was the last survivor of an Execution Force sent to kill him. When the assassin reached Aun'Va in his command bunker, the Supreme Ethereal was sent fleeing, gravely wounded and alone into the dark streets of the abandoned hive city above, having watched every T'au warrior and drone thrown against the assassin get torn to shreds before his very eyes. What happened to Aun'Va isn't stated, but the ignominious death of this powerful xenos leader is noted to have been neither quick nor painless. The circumstances of his assassination are stated to be so horrifying and demoralizing that the T'au leadership conspired to cover up his death with a holographic simulacrum in order to prevent the entire empire from collapsing into chaos and despair should they learn the truth.
  • The third is the Callidus Temple. Comprised predominantly of female agents, the Callidus use a Fantastic Drug called "Polymorphine" that lets them change shape into anyone — anyone — a process that often involves breaking and resetting their own bones as part of the transformation. They're often used for terror tactics and discreet "warnings" — one famous Callidus is "Mother Gullet", who stopped a potential rebellion by disguising herself as the elderly nursemaid of the governor's infant son, sneaking into his room, and then using her shapechanging powers to distend her mouth and gullet so that she could swallow him whole, before escaping, unslowed by the distension of her belly. The disappearance (it's implied she digested the baby) broke the governor's spirit and caused him to lose any ideas of rebelling. When they do need to assassinate victims, they use a gun that scrambles people's brains and a C'tan Phase Sword, an otherworldly blade that can cut through anything — even forcefields.
    • Admittedly, this leads to a hilarious Always a Bigger Fish incident in the first Necron codex to feature the C'tan; a Callidus attempts to assassinate a person who has already been replaced by the Deceiver. He simply absorbs the blade when she stabs him with it (it's made from the same metal as his body) and then sucks out her life-energy for a snack.
    • Ironically, the story of Mother Gullet is made less scary when updated to 8th edition; the version told in the semi-official Assassins codex in the March 2019 issue of White Dwarf reveals that she didn't digest the baby, she just abducted it and delivered it alive to her superiors, who used him as leverage to force the governor to fall back into line.
    • The Callidus assassin in Death's Hand casually cuts her hand in half just to prove a point before reassembling it.
  • The fourth, and last of the major ones, is the Vindicare Temple, which produces the absolute best snipers in the Imperium, armed with weapons so powerful they can break an ordinary man's arms with the recoil from one shot, who are capable of waiting completely motionless for days on end in the most ridiculously hostile conditions to make the perfect shot.
    • Just after the aforemetioned Callidus in Death's Hand cuts her hand in half, she lies her head to the side as a Vindicare on the ship several dozen kilometers away puts a shot right between the eyes of target and, using the same hole in the window he just made, destroys the Callidus's restraints.
  • There are two minor subtypes, the Vanus (the intelligence arm), and the Venenum (poison experts short of Chaos and Dark Eldar), which don't seem that bad, but then there's the Maerorus, which could best be described as Alex Mercer from [PROTOTYPE]. And they're not sure they got all of the eggs to boot.
    • And even those two minor ones do have their terrifying elements, they're just tame compared to everything else. Venenum assassins have access to some of the worst poisons the galaxy has to offer, and have something for every enemy, from simple xenos to daemons, and their delivery methods can be so unorthodox they can always get you from an unexpected angle. Vanus assassins are The Chessmaster, and if whatever side you're on has anything even resembling sentience they can arrange your death without you ever knowing what happened; anything from simply providing invaluable intel to the real killers to such vicious slander your own allies will put you down.
  • While not particularly terrifying, here are a few incidents that show just how much power the Officio Assassinorum wields. The first one is the Beheading in the M32. The Grand Master Drakan Vangorich completely wiped out Council of the High Lords of Terra effectively leaving the Imperium without any form of centralized command.note  In response a strike force was formed from the multiple chapters consisting of roughly 1000 Astartes to eliminate renegade Grand Master. The strike force was ambushed by one hundred Eversor Assassins and wiped to the last man while barely being able to complete the objective.
    • The other one happened during Age of Apostasy, a civil war that engulfed the Imperium in M36. The unseen wars broke off between assassins loyal to renegade Ecclesiarch Goge Vadire and those loyal to faction of Sebastian Thor in the heart of Holy Terra. Use of ancient Dark Age and xenos weaponry resulted in destruction of entire wings of the Imperial Palace, Mankind's Greatest Fortress.

  • Every single little detail about Psykers is horrific:
    • Their abilities come from the Warp, so most of their time is spent dreaming about Daemon Worlds with black suns or boiling lakes of blood or clouds of disease and death, or being tempted by the servants of the Chaos Gods with visions of power and suffering and glory and death. How this plays out for them depends on a number of factors:
    • If they're really lucky, they're killed in a pogrom after their fearful and superstitious fellow humans discover they're a psyker.
    • The less lucky ones are found by the Black Ships (roving fleets that visit a planet every century or so and collect all the psykers present) and killed by being "fed" to the Emperor to maintain the Astronomicon (the psychic beacon that allows accurate Warp travel).
    • The unlucky ones are "acquired" by various departments of the Imperium for a particular purpose, ranging from a human communication beacon (the process of creation resulting in, at best, empty eye sockets and often complete loss of sanity), to a Sanctioned or Battle psyker prone to having a daemon hijack their body and soul and even more prone to be executed at suspicion of possession, to the best being allowed the "honour" of training to become an Inquisitor, a Space Marine Librarian or even a Grey Knight, which involves the aforementioned horrific training of a Space Marine coupled with a healthy dose of Mind Rape.
    • The really unlucky ones are not discovered at all, their constant visions driving them to madness and allowing the endless hordes of the Warp to use their skull as a portal and rip themselves into the material realm, quickly consuming the entire planet. If the Enslavers don't get there first. And then there's the Chaos versions.
      "Imagine knowing there was a door to the realm of daemons, and the slightest inattention on your behalf would see them batter it down and rip you to shreds. Now imagine that door is inside your head. That's what being a psyker is like." —Castus Lupa, Savant Adjunct
  • ...and then there are Pariahs. Think of every reason you have to not want to be a Psyker, then throw it in reverse, full tilt. You're effectively soulless, cast no light in the Warp and are damned to be an outcast from any and all societies you encounter. At best, you'll end up as an assassin for the Inquisition, or get scooped up by the Necrons to be turned into yet another form of soulless abomination, half flesh and half necrodermis.
    • Just to iterate a bit further, Pariahs radiate a sensation of wrongness to those around them and generally make people uncomfortable. This means that in a truly Crapsack World setting, you can't hold a job, or have a friend, or go to the Emperor's Church (this last one will probably result in the priests labeling you an abomination anyway) - you can't even resort to basic prostitution as only those too drugged out of their minds to notice or those who thrive on your lack of Warp-reflection will "get with you". And if you happen to cross a psyker's path by accident, that psyker WILL take notice of you since your lack of a warp-presence will physically hurt him. Imagine what will happen if you, an extremely rare phenomenon, were to cross the path of a psyker who has some friends very interested in "examining" rare phenomena. Not everyone is Gregor Eisenhorn, y'know.
  • And then there's Spear, the Black Pariah who cranks the above up to 11 and has a daemon bound to his SKIN.
  • Want to know something really scary about Psykers? They're part of the Emperor's endgame plan: keep himself alive long enough for humanity to evolve and develop enough psykers so that they can fight Chaos on equal terms. The only hope humanity has is for the entire race to become psykers.

  • The Imperium hates mutants. Genetic purity is central to their religious ideology. And because of how decentralized the various factions of the Imperium are, and how tangled their bureaucracy is, there's no real defined guideline as to what defines "mutation". Most mainstream Imperials would agree that even something as innocuous as heterochromia or an extra digit — traits seen in real life humans! — warrants casting down to the role of an oppressed slave-caste, if not death on sight. In some corners of the Imperium, even things as minor as the "wrong" skin, hair or eye color can result in one being deemed a mutant and punished accordingly.
    • One of the most horrifying bits of mutation-related lore? The planet of Lastrati. In the name of genetic purity, they conducted nightmarish genetic pogroms, including infecting their population with multiple gene-targeting viruses in an effort to wipe out "undesirable" traits. When a Black Templars crusade dropped by, they found a population that had once numbered over 14 billion people had been reduced to 2.5 million, both by the viruses and the human sacrifices. Lastrati was a HIVE WORLD. The Black Templars were so horrified by the extent of the carnage that they declared the planet to have been subverted by Chaos and massacred the Quintarchs, the ruling cliques of Lastrati, to end the pogroms with the Second Purging of Lastrati. To put this in the proper perspective, the Black Templars are themselves the most fanatical of the Space Marine chapters, existing in a constant state of rage-fueled crusading with a hatred of mutation so intense that they refuse to field Librarians yet even they were horrified by the anti-mutant zeal of the Lastrati. Also, in a very, very rare act of mercy, they spared the surviving population of the planet.

Servitors are either vat-grown clones or criminals/dissidents/failed teammates (usually the second - there is no shortage of troublemakers...) who are lobotomized so that they cannot act without bio-programs from the setting's tech-priests. They then have useful cybernetics attached to their bodies, be they engineering tools, sensors, calculators, or heavy weapons. Since the Imperium has a ban on artificial intelligences, some servitors are simply wired into vehicles or other machines to serve as semi-organic computers. The one saving grace is that there is little enough mind left that the Servitors are even sentient anymore. Hopefully. There are some who speculate that the mind-wiping process may not always prove 100% effective, and that the fragmented remains of servitors' consciousness are still trapped in there, desperately trying to piece themselves together.
  • Sometimes you actually feel that is not that they are adding mechanical parts to a human body, but that they are adding human body parts to a machine.
  • You know where many combat servitors come from? From a system where there is an official sanitarium for Imperial Guardsmen suffering combat trauma. May or may not be a coincidence. Probably not.
  • Yeah. Totally a coincidence, considering the near-useless Imperial Infantryman's Uplifting Primer says on page 11 that troopers who break regulation or otherwise fail to meet expectations have the potential to be made into servitors. The overall wrongness of servitors has already been explained, but that adds a whole new level of wrongness. They flat out tell troopers in a Big Book of War meant to increase morale that they will be lobotomized, have their identities erased, and be Mind Raped into semi-organic computers with no free will. And people wonder why the Imperial Guard is a Red Shirt Army on a bad day!
  • Here's a quote describing the Aceptus Mechanicus' Battle Servitors:
    "The servitors of the Adeptus Mechanicus are the lowliest of all the Machine God’s servants, dispensable cyborg warriors that are thrown into battle with absolutely no regard for their safety or survival. Should they be killed, their mechanical parts are recovered, repaired and fitted to a new, unwilling host. Their mortal remains are liquidised and fed to their successors as nutritious gruel. And so the cycle continues."
  • On the subject of servitors: arco-flagellants. Oh god. Criminals and heretics forcibly re-educated, their arms replaced with horrid powered melee weapons like electro-flails, cybernetics all over their wasted forms, drug feeds hooked up to their bodies, and their faces covered in a blank mask. Normally rather passive, kept in a permanent trance of religious images (and this is the Church Militant of the 40k 'verse) and calming thoughts. Say the word, and the arco-flagellant goes berserk, butchering everything in its path. As well as the Penitent Engines, devices designed to cause torture even worse than arco-flagellation. And, to top it all off, the Church Militant seems to think that even these torture devices are not horrific enough, and is always trying to invent new ones.
    • To clarify, these are not Servitors, because they don't get mind-wiped. There's still a human mind in there. And why in the Holy Emperor's name did they invent such a punishment? Because death was too good for them.
    • As aforementioned in the the Inquisition section, sometimes the arco-flagellant in question was selected because they were deemed redeemable in some form if they serve properly. As detailed in the Chaos section, a temporary Fate Worse than Death is far preferable to the variousdelightful And I Must Scream scenarios that can be inflicted to corrupted souls.
    • Lords of Mars provides an in-depth description of the arco-flagellant conversion process, viewed through the eyes of a man reliving one such flagellant's memories. Highlights of the hours-long procedure include the flagellant's arms being flayed down to the bone before artificial muscle is grafted on, weapons being bolted through flesh and onto the bone, and his eyes being torn out and replaced with hard-wired targeting arrays - all while fully conscious and aware of what is happening to him.
  • There's also the Cherubim, which are flying servitors created out of vat grown babies. They often serve no practical purpose, instead being status symbols of the rich and powerful. And no, whatever their creators' intention, they always come out as pudgy, unhealthily pasty little flying angels whose faces tend to be more skull-like than cherubic. Best of all, their brains/bio-programming are derived from animals such as pigs or dogs, so they sometimes go "feral" and make for your throat.
    • There are "better" versions of the Cherubim called Nephilim, which are made from children. Particularly prized are latent psyker kids, even unborn ones, because another psyker can attune to them like a familiar. Oh, and it has to be a child below the age of 6, or the bones are too heavy.
    • One Tech-priest in the Soul Drinkers series keeps a number of Cherubim around apparently just to unnerve everyone he works with.
  • An unconfirmed source from the Human Resources page claims that some parts of the Juvenat Process are derived from children. Yes, that means that the elite of the Imperium and even Ciaphas Cain (HERO OF THE IMPERIUM) bathe in children. Blood Countess, anyone?
  • Servitor bodies are culled from clones or criminals condemned to death. Do you know what crimes constitute becoming a servitor? Anything from being a Serial Killer to stealing from the temple's donation basket.
  • On a more horrifying level is the fact that some of the fluff about forge worlds (particularly from the RPG books) imply that if workers are inefficient as humans they are repurposed as servitors. Note this isn't a punishment or being made an example of to increase the efforts of others it is simply the mechanicus being more efficient..... Imagine living in a world where if you are not vital or productive enough you will be turned into a meat robot......
  • The ultimate nightmare of servitors is not how horrific they are, but how normal they are. These enslaved cybernetic human half-minds are as embedded into the society of the Imperium as tablets and microchips are in ours. They will hand you your tickets, call up from reception, do your taxes, even just act as status symbols. Servitors are the ultimate example of the Imperium's complete disregard for the humanity it is meant to preserve. The trauma of the Iron War weighs so heavily on every human survivor of the Age of Strife and especially the Mechanicus that anyone trying to use Abominable Intelligence is immediately marked for death and the alternate method of using cloned brains with no memory or punished criminals (of any stripe, from a mother forcibly dragged away from her children after failing to meet quotas or a serial killer, depending on the planet or servitor type) as wetware is considered a better alternative.

    Imperium and general background material 
  • The Imperium itself is what happens if George Orwell teams up with H. P. Lovecraft to create the worst dystopia ever, where the super-totalitarian, heresy-crushing regime of Nineteen Eighty-Four is all that keeps human civilization surviving against hordes of reality-warping, insanity-inducing Eldritch abominations. Even some of the very ideologies of the Imperium are scary:
    Every human life is a spark in the darkness. It flares for a moment, catches the eye, and is gone forever. A retinal after-image that fades and is obscured forever by newer, brighter lights.
    • Perhaps an example will better define how horrific the Imperium is at heart. The planet Veyna was colonised in 068.M41, and rather than setting it up as the standard "you do X for the Emperor" planet, the Adeptus Mechanicus spotted the lakes of liquid hydrogen on its poles and claimed all the land for a processing plant rather than continue creating their own. Instead of simply placing the inhabitants to live out their lives on a nearby planet, all but the most rebellious (who fought a guerrilla war to no great effect) were herded off to a forge-world and worked to death. No-one in the Imperium who knew considered this anything unusual or unethical in any way.
  • Dark Heresy's introduced the appropriately-named Death World Phyrr, which makes Catachan look like a cakewalk. To put this in perspective, Catachan is a jungle world on which most organisms—including plant life—are carnivorous (which includes insects the size of heavy tanks and explosive amphibians), and living past the age of ten is a major achievement. Phyrr is a planet on which all organisms are lethal to non-native life, down to a genetic level. A mere handful of native plant spores—any plant—can kill a man within an hour, assuming that he isn't killed by any number of carnivorous or toxic beasts first.
    • And the Mechanicus know it, too. Phyrr is home to a penal colony they remotely operate from the moon that doubles as a facility to harvest the same toxins that make the planet so fearsome. This prison is staffed by criminals sentenced to death, goes through a complete turnover every few years, and yet it has no guards, no walls, no security systems of any kind—except Phyrr itself. Imagine being an inmate and forgetting to follow one single decontamination procedure on a whole laundry list of them. You're dead. Your cellmates getting restless and wanting to break out? The Mechanicus can just flick a switch to turn off every single air filter in the facility. You're dead. And if you somehow find a bio-suit before all that and somehow manage to escape? Read the paragraph above. You're dead.
  • While we're on the subject of Imperial worlds:
    • The entry below, while doing a good job of describing the life of the average Imperial citizen, does not do the average Hive World justice. They're lawless, corrupt, dirty places like the Kowloon Walled City taken up to roughly 21, with no rules, no law to speak of, polluted to the gills and damn near uninhabitable once you get deep enough due to thousands of years of pollution, and you're constantly at risk of alien invasion, murder at the hand of a horrible gang, or the Imperium itself. Either you'll get caught in an Imperial culling where they kill citizens to keep the population at manageable levels note  and die, or join the army or Space Marines (Their aforementioned horror notwithstanding.) and then die. Why would the denizens of a dirty, polluted Hive World be chosen to join the Emperor's Finest and the Imperial Guard, both of whom are expected in incredibly dangerous situations that would on average make us shit our pants? Because Hive Worlds are thought to be as dangerous as Feral Worlds. Yes, the average Imperial citizen lives in an environment considered as dangerous as a jungle in the stone age, except the inhabitants have guns and worse.
    • And Forge Worlds, worlds dedicated to production of useful goods, are like Hive Worlds but worse because they have even more pollution, and they're run by the Adeptus Mechanicus. If you've gotten this far, you should know why that's a bad thing, but to elaborate they rival the Administratum for being callous bastards.
  • Imagine being a common, normal human in this. To paraphrase one of the comic books, "We used to pray that the Emperor would send his angels to save us. Now we pray he never does again."
    • To expand on this, imagine being one of quadrillions (or quintillions, and these are conservative estimates, in the highest Terra alone has quintillions let alone other hive worlds and the other planets/stations/moons) of human beings alive in the Imperium. Imagine living in a hive planet, which is basically an entire planet hollowed out and turned into a single giant city where countless other humans live and all your food and water are probably imported from some agriplanet. Imagine being at the mercy of an unthinkably massive government, one that views you at best as a resource to be used as they say fit (as a citizen of the Imperium, you have no rights, just responsibilities). On top of some incredibly shitty job (think 12 hours of factory work a day), imagine also having to worry about the incredible amounts of crime all around you. Imagine knowing that, at any moment, the authorities might take you in for any crime (guilty or innocent), and do whatever they please. Imagine being taught from birth that your entire existence is to be a servant to the Emperor, a lesson which everyone around you has learned very, very well. Imagine knowing that any amount of heresy, of any kind, you might display will land you, at best, a very quick death. Then, remember that doesn't account for all the xenos, heretics, and so on that exist all around, and that, with every coming day, the chance of being killed by some invading fleet, your own government, or something similar can only get stronger. Yeah, the Imperium sucks.
  • So why is it like this? Well - The Extremist Was Right in the Imperium. Consistently. There's a quote found in the book Dark Adeptus by Ben Counter that reads: "In ancient times, men built wonders, laid claim to the stars and sought to better themselves for the good of all. But we are much wiser now." Unsettling already, but it gets worse once you realize that from the Imperium's perspective (as opposed to Fourth Wall Myopia and disregarding the fact that most Imperial citizens have nothing close to the birds eye view that Codexes and books give, only ten thousand years of institutional pressure attempting to prevent the five thousand years of catastrophe suffered before it, all the while being subject to the whims of various Eldritch Abomination attacks), they really are right to think so. Horrified at the existence of Servitors, or hate the Adeptus Mechanicus for having a stranglehold on Imperial tech? As bad as they can be, there's justifications because of prohibitions to artificial intelligence that were set in place because of a Robot War, countless daemonic possessions of technology, and numerous successive galaxy-spanning apocalypses. Fear of innovation? It has an alarming history of killing all of them. Hatred of psykers? They can kinda summon demons from the Warp on accident, and some of the only worlds that survived the Age of Strife did so because they took it upon themselves to murder psykers. The Inquisition acting as State Sec and the memetic tendency towards shooting "heretics"? Chaos is just that bad. The Radical Inquisitors who Became Their Own Antithesis, making use of xenotech and chaos-corrupted weaponry? Their job is just that awful, and the sacrifices they make may not just be practical, they may be the only options to preserve the Imperium, even if they involve the possible death of billions. The Imperium itself is a bureaucratic, despotic, theocratic, Orwellian, xenocidal hellhole, basically Nineteen Eighty-Four In Space so that it can never undergo another Horus Heresy, even if it means internal strife and struggle on a massive scale. However, when one reads the Horus Heresy series itself, it suddenly becomes clear that this is still a good thing.
  • Now that you've grasped the living nightmare that is life in the Imperium, imagine being an alien in the Imperium's way. The Imperium preaches xenocidal hatred as a matter of principle, and will utterly exterminate any alien race it can, whether or not it might pose a threat. So let's say you're an alien, living on your own little planet, which, likely, is your entire universe. Your scientific understanding might barely equal that of the Greeks and Romans; you might not even be aware of space, let alone the threats it could contain. Then, suddenly, the sky is torn apart by fire, and the clouds begin to seethe. Your largest cities and greatest monuments are blown to dust in an instant by hammers of light from beyond heaven. Your mountains ring with thunder and your rivers rear like serpents as your world is hit with shock after shock. And then, for the crime of mere survival, you must face the next wave; a horde of hideously-armoured, beweaponed creatures that may look utterly unlike you or anything you've seen, marching methodically across the ashes of your culture, seeking you out, hunting you down, determined to kill you, your family, your friends, and everyone you know, simply because you are not them. And they will not stop until they do, even if it takes thousands of years. They consider hatred, ignorance, and fear to be virtues, and they absolutely cannot be reasoned with. With that in mind, it's small wonder that humans are considered to be another flavor of Ork by other civilizations.
    • On another note: If they're more advanced than you, then you're doomed. If you're more advanced than them, they have more reserves than you could possibly dream of ever fielding. But you won't know that, you'll only know that they never run out. At this point, the only option is quite likely to trust the Tau. Which... hopefully turns out well. Hopefully. Oh, and the Tau are a moderate power in one corner of the galaxy and said corner is currently the target of multiple WAAAAGH!s, a Hive Fleet, several Necron Dynasties and is next to Ultramar, the most stable Imperial-sub realm. Other moderate powers like the Q'Orl are no better than the Imperium, as anyone peaceful has long been torn to pieces by Orks or turned to ash by Imperial military efforts to clear colony candidates.
    • There's a brilliantly written moment in the story Blades of Damocles where a Tau commander examines the smoldering wreck of a Space Marine Dreadnought after a battle. He believed the Dreadnought to be just an unmanned drone and was horrified to find the Space Marine still alive inside the chest cavity, screaming profanities at him and demanding to be finished off. What the scanners revealed to the commander made his blood run cold: what he was looking at was a mutilated wreck of a human that had been entombed in this armoured war-coffin for six thousand years, long before his species had even ventured out of their caves. Even to the Tau, the Imperium represent the ultimate existential dread.
    • Now imagine why the Imperium does this - not only is the extremist right, but the Imperium's respective advocates of killing every alien have been right so often that their violent methods are not only justified, but quite likely the only way to be sure. In the early days of the Imperium, mankind was weak after the government collapsed in the Age of Strife and often suffered the depredations of xenos, so overwhelming force was the only option. However, with countless runs of bad luck (Poor Communication Kills was a common problem during the Horus Heresy) and fighting aliens that genuinely deserved to be wiped out, they are unlikely to change. It is theorized that the Emperor placed the kill all aliens order in order to prevent even a pacifistic alien species to be overwhelmed by the plague of psykers and cause a daemonic invasion or invent AI and unwittingly repeat the human mistake on that count. With him incapacitated and with ten thousand years of only allying in desperation or pragmatism and only with a select handful of species like the Eldar or Tau, killing all aliens is simply a fact of life and Imperial citizens are legitimately disgusted on a personal level with all aliens (even a generally decent person like Commissar Ciaphas Cain, HERO OF THE IMPERIUM, is horrified at Tau sympathizers, because he knows Chaos can get its hooks in through any form of acceptance of foreign ideas). When combined with monsters like the Dark Eldar and Living Weapon Ork hordes and the depredations suffered in the Age of Strife; fear and hatred have become celebrated by humanity.
    • It's also worth mentioning: If you're a human in the Imperium's way, you're slightly safer than a xenos. Slightly. Everything about the previous entries still applies. Going by Peter Fehervari's novel Requiem Infernal, the Imperium's first discovery of inhabited human worlds can go... poorly. If you try and fight them, it results in battalions of Space Marines and Imperial Guard destroying your civilization's strongest troops and weapons almost effortlessly. In that case, the Imperium still managed to negotiate their surrender, but there's always the risk that the Imperium will just bombard it into submission without ever considering diplomacy. If you try to join the Tau, that comes with its own (writer-dependent) hardships, and will almost certainly result in your home becoming a war zone at some point. The best-case scenario is to refuse to fight, join the Imperium, pay the tithes, and keep your head down. But that requires becoming part of this utter nightmare world, and being subject to the myriad cruelties of the Arbites and Ecclesiarchy, watching your culture become subsumed by the Imperium's. And, hypothetically, if your civilization made contact with Aliens, the Imperium will have made efforts to prop up local anti-alien movements to ease you into the Imperium.
      • Case in point, the story of Imperial Missionary Genevieve Almace. Upon finding a world that, through some miracle, retained peaceful human and xenos cohabitation she felt legitimately disgusted and incited a rebellion that destroyed the xenos species.
  • Since we mentioned the Horus Heresy - the Great Crusade counts as this when you think about it. Imagine every fascist expansionist movement on the typical scale of Warhammer 40k... then imagine it on a literally galactic scale, because this was when the Imperium set to conquering worlds, murdering entire races, and razing independent humans that survived the Age of Strife that simply didn't want to be part of the Emperor's vision. All of this would've been when the Imperium was arguably even more terrifying, with Space Marines fielded in larger numbers, Baneblades as the "mainstay," and numerous archeotech from the Dark Age at their disposal.
  • The Dark Age of Technology itself is genuinely unsettling when you consider the implications. It's been said of Dark Heresy that "Ancient Alien artifacts are scary, ancient magic artifacts are scarier, but ancient human artifacts are the stuff of nightmares." And it's true. All the advanced technology we see the Imperium of Man fielding against Chaos and other enemies - genetic enhancement used to create Astartes, Humongous Mecha, self-recharging laser rifles, Terminator Armor? Children's toys and infinitesimal fragments compared to the feats of Dark Age humanity. Probably the best example of Dark Age technology is the Speranza's most infamous weapon, a chronoweapon that creates small temporary black holes and also distort time so that even if they miss, the enemy is teleported nanoseconds back in time to occupy the same position as their past selves simultaneously, resulting in both versions being destroyed, i.e. a gun that literally causes targets to telefrag themselves. This was apparently meant to damage Dark Age ships, not kill them. According to Ollanius Pius, who observed the Dark Age, the Horus Heresy was a mere skirmish compared to the wars that ended the Dark Age.
  • Within the Calixis Sector, there exists a phenomenon called Komus, or the Tyrant Star. No two appearances of it are exactly the same, but its arrival comes with signs months ahead of time- maddening visions, mass panic, a rise in fanatical religions, a spike in mutations and psyker activity, geologic upheaval and odd runic sigils appearing on walls or as birthmarks. Finally, Komus typically appears as a black sun that eclipses a system's native star, emitting pale light and esoteric forms of radiation for several days, only to disappear just as inexplicably. Some sources claim it may sometimes appear as a strangely bright star at night, a phantom corona around a moon, or it may only be visible as a reflection in mirrors or pools. All appearances, however, come with the same effect: a force that transmutes human minds and makes them ready to embrace the darkness.
    • So what is it? Nobody knows. There are obvious parallels to Chaos and the Warp, but Komus seems to be its own phenomenon; it also has potential connections to the Tyranids and Eldar, given the references to devouring, but there's no obvious connection to any of them. The Calixis Sector is known to have been home to ancient and powerful xeno civilizations many eons ago, and many of them do make mention of the Tyrant Star, suggesting it's far older...
    • The Inquisition is very interested in the phenomenon, as it has a place in a wider prophecy known as the Hereticus Tenebrae, which speaks of a "darkness" that will bring about the extinction of mankind, which will have its origins in the Calixis Sector. The visions Komus provides may provide vital in decoding it, but it's been nearly impossible to decipher; the most obvious term found in it is "devour." The actual text of the prophecy is locked in the Bastion Serpentis archives, and Lord Inquisitor Zerbe allows very few to read and analyze the complete transcript. But with how often the entire sector breeds heretics and fanatical cults, it may be impossible to decipher the prophecy before whatever it describes makes itself known.

Xenos Races

  • Tyranids. Like Giger's Aliens, but smarter, meaner and a helluva lot bigger. They come in an ever-growing range of sizes and shapes, from human-sized monsters to living Humongous Mecha, all deliberately evolved towards a single purpose. They have biological ranged weapons that spray acid and venom or fire swarms of flesh-eating maggots via muscle spasms. When they attack your world, they send vanguard organisms to corrupt your genes, resulting in a cult of hybrids that psychically summons the hive fleet. Note that these vanguard organisms themselves are terrifying creatures that exceed the human potential of speed, dexterity, strength, resilience, and sheer terror so many times over that these are often enough to cause widespread genocide in and of themselves. Once the hive fleet arrives, they seed your atmosphere with spores that drive plant life into a growing frenzy, then they rain down swarm after swarm after swarm of chittering monsters. These range from uncountable numbers of lowly Gaunts, who are cannon fodder which is more than capable of disemboweling you, to Carnifexes, which rival a tank in firepower and toughness, to the lumbering Bio-Titans, which make Godzilla look like a pet iguana - a nice iguana, at that. The Hive Mind of the species disrupts space travel and psychic communication, so there's no way to call for help and no way for it to arrive, and no way for the tasty little bioforms to escape. Once they've overrun whatever pathetic resistance you attempt, they send down speciality creatures to eat everything on your planet - plants, animals, even their own troops. The fleet sends down feeder tendrils to slurp up this digested bio-fuel and siphon the very water and atmosphere off of your world, leaving it a lifeless rock. After consuming everything, they instinctively scan the DNA of the creatures they've devoured for useful evolutions they use to upgrade the swarms, before moving on to the next world.
  • There are two throwaway pieces of background in the current Tyranid Codex (i.e. rulebook) that are particularly horrifying:
    1. During the first ever human encounter with the Tyranid race, they hit a mining world. It basically turns into The Descent IN SPACE! with vast hordes of terrifying alien monstrosities. Alien 3 done right.
    2. A little later in the timeline, a ship full of refugees from a world under attack from the Tyranids turns up at its destination, drifting lifelessly in space and not responding to any attempts to communicate. When the Imperium investigates, they find that every. Single. Person. On the ship has been brutally slaughtered. But there is no sign whatsoever of the thing that did this.
  • The Lictor is custom made for this trope. Over two metres in height, possessing both massive scythes for tearing apart tanks and delicate tendrils for eating brains (from which it absorbs the victim's knowledge), it is so ridiculously agile and stealthy its targets are often not even aware of its presense until after they find themselves severed at the torso, and it is not uncommon for their skin to be chameleonic to further aid in infiltration. It also has a tendency to exude chemical signals to draw other Tyranids to its location with the amount produced directly related to the size of resistance, so even if you do manage to kill it you then have to deal with the rest of its friends.
    • Deathleaper, a special Lictor, takes this slightly further. Suffice to say, something which can go back into hiding quicker than your troops can react AND has been tormenting a character in your army for a long time isn't fun to fight the first time.
      • The fluff about Deathleaper is even worse. The first recorded occurrence of the creature was on a heavily fortified Imperial shrine world that the Hive Mind decided was too strong to take in a head-on attack. It installed Deathleaper there and told it to find the leader of the planet and assassinate him. After stalking for a while, Deathleaper found the governor of the planet and attempted to kill him, but was repulsed by his bodyguards. So it began a campaign of psychological terror - every day it would infiltrate the governor's palace, butcher its way to the governor but then leave him unharmed. The governor had to deal with the loss of his advisers, scientists, commanders, friends, bodyguards and family, until it got to the point where Deathleaper entered the room the governor was residing in, killed everyone inside except for his target, and left him sniveling on the ground, coated in the viscera of his friends and allies. He took his own life minutes after this attack, leaving the defences of the planet thrown into disarray. The Hive Fleet consumed the world within the end of the week. Be glad the psychological warfare rule he has only deducts d3 LD from an enemy character.
  • Think the Lictor was bad? Meet the Norn Emissary. A gigantic Tyranid Warrior with multiple scythe claws that can tear apart Custodes armor, a mind as keen as the Swarmlord's (sans the autonomy), and only lacking the chameleonic skin (for now). They're just as agile and cunning as their smaller cousins, but they hit far harder, and they're specifically designed to assassinate key leaders and destroy crucial installations. They're essentially the Tyranids' answer to the Eversor Assassins, only far smarter and even meaner. One of these things tore through a Custodes squad like they were Guardsmen, and only Trajan Valoris himself was able to kill it. And until it launched itself at its target, no-one even knew it was there...
  • The Imperium has currently encountered three major Tyranid Hive Fleets:
    • Behemoth, which had over a thousand hive ships and countless other smaller ships and Emperor knows how many ground organisms, which killed the entire Ultramarines first company and almost devoured Ultramar. To put that in perspective, the hundred strong Ultramarines First Company was composed entirely of veteran Terminators. They had a well-fortified position, and enough ammunition and supplies for months of continuous siege, yet they still almost ran out of ammo. They killed millions, enough that the ground wasn't visible under all the corpses. And one of the early worlds that was overrun had all of its anti-air guns found bone-dry of ammunition. The Tyranids simply had more bodies than the defenders had bullets.
    • Kraken, which was much, much bigger than Behemoth (Behemoth was only 30-40% the size of Kraken), was the first to use Genestealers as shock troops, and nearly destroyed the Iyanden Craftworld and the planet Ichar IV with tendrils that were themselves as big as the whole of Hive Fleet Behemoth, if not bigger. Genestealers had previously been believed to be predators native to one of the moons of Ymgarl; in fact, these Ymgarl Genestealers were the Tyranid equivalent of cancer cells, defective and unstable biofroms that the Hive Fleets left behind wherever they could. This lead to the Adeptus Mechanicus coming to the horrifying realization that the Tyranids had been in the galaxy long before the first appearance of Behemoth, meaning they'd been here before, and they hadn't left anyone alive to tell the tale.
    • Finally, Leviathan, which puts Behemoth and Kraken to shame in size. First appearing in 997.M41, it crashed into humanity's defenses in the galactic east. This would have been bad enough, only it then turned out Leviathan was coming at them from below the galactic plane, meaning they'd be able to strike theoretically anywhere. Planets were burned en masse to try and starve the fleet and/or slow them down, culminating in both the disastrous Octarius War between the Tyranids and the Orks, and the Devastation of Baal, the Tyranid siege of the Blood Angels homeworld. Leviathan seemed to have been stalled when the Great Rift opened, only for it to suddenly rear up in the galactic west with more monstrous forms than ever before, attacks coming from both above and below the galactic plane. The galaxy is officially surrounded, and the jaws of Leviathan are closing on Terra.
    • Such are the Tyranids numbers, an old quote from a 4E-era White Dwarf, claimed that if every bullet in the galaxy was fired at - and successfully killed - a Tyranid, not only would it not destroy them, there would still be enough to conquer the entire galaxy. Between the Orks, the Imperium, Chaos, and all the various other races, think about how militarized the Warhammer 40k galaxy is and let that little factoid sink in for a minute.
  • One must wonder if some of the new game-breakingly powerful specialised Tyranid breeds are. Subject One - the Doom of Malan'tai. In its fluff, it destroyed an entire craftworld by literally eating the souls of the dead from the Infinity Circuit. Now just stop and freeze frame a second. There's no sign of the creature, but who's to say it hasn't found a way off? Who's to say all the souls it's eaten didn't give it protection from the vaccum of space? Who's to say that a bad codex writer didn't just put the God Emperor in the form of a Tyranid? Who knows how many souls it's eaten since, and how much power it now has?
    • Another less powerful but still nasty fleet was Hive Fleet Naga, whose accomplishments include the devouring of four outer colonies and the Throneworld of the Ulumeathic League, the wiping out of the Ybaric Cluster, and the destruction of two Eldar Maiden Worlds and seven Exodite Worlds, including by crippling the world spirits of several Exodite worlds by the devouring of a single Exodite world. Also, they created the Doom of Malan'tai.
  • The Venomthrope is covered in tentacles and sprays venom, spore clouds, and all sorts of assorted toxic monstrosities at its enemies. Trygons and Mawlocks are huge snake-like monsters that can burst up from any point of the ground whenever they please. These are just some of the lovely things you can find in the 5th edition codex.
  • The battle of Sondheim V. A peaceful Agri-world in the Imperium of Man that has been up to that point far removed from any conflict for thousands of years suddenly sees the skies turn into a multihued mess as the Daemon prince M'kar the Reborn decides to turn it into his private playhouse and Daemons start running loose everywhere. But soon after this a tendril of Hive Fleet Leviathan descends upon the planet and the sky starts glowing in other weird colors as endless numbers of Mycenic spores rain down upon the planet. Gaunts, Genestealers, and Warriors start fighting Bloodletters, Horrors, Daemonettes and Plaguebearers, utterly undeterred by their Daemonic nature. Gargoyles and Furies gnash and tear at one another in the skies while Carnifexes, Tyrannofexes, Hive Tyrants, and all sorts of bio-titans fight Greater Daemons in the streets. Nurglings and Rippers devour one another while Zoanthropes fight psychically with Lords of Change. Now this may sound awesome, but imagine if you were just a normal Imperial Citizen cowering under his bed while watching two of the greatest horrors in the Galaxy have a go at each other. The entire Sky Sentinels chapter is sent to reclaim the planet, but the whole thing is so terrifying that they just decide to Exterminatus the place and blow up the hive fleet tendril.
    • Speaking of Exterminatus... it's not guaranteed to wipe out every Tyranid on the planet. On one occasion, an Imperial team was sent to examine a world that was hit with Exterminatus to halt a Tyranid invasion, and what they thought was a rock formation was really a Carnifex that had gone into a dormant state to regenerate from its injuries. There have also been instances of Tyranid organisms burrowing down into the ground to escape the devestation on the surface, only to emerge once they sense life forms on the planet again.
  • The Shadow in the Warp:
    • The mass of Tyranids in the hive fleet is so incredibly huge, the subconscious buzz of all their minds adds up to drown out the Warp. This renders all FTL travel and communications impossible, and presumably also makes Daemons shit themselves.
    • The description of exactly what the Shadow is can be utterly terrifying on it's own. Most sources describe it as simply static, but one story has a first hand account. It is the collective voice of every single tyranid organism screaming in unison in hunger. And the reason it drowns out the warp is because the minds are so unified in a single purpose that the chaos gods cannot get a word in edgewise. This is also why Tyranids cannot be corrupted; they have no reason, no morals, no desire. They only feel the primal need to feed. And they will feed.
    • This extends to the Hivemind as well. Unlike other depictions of a hive mind, where an overriding central intelligence controls it's various minions telepathically, the Tyranid Hivemind is quite literal; it is the conglomeration of every single tyrannoform thinking in unison. The reason the Shadow in the Warp is the screaming of every tyranid mind? That is the Hivemind's sole thought. There is no central mastermind to the tyranid race. There is no single being they can kill to stop the threat. The only way to end it is to annhilate every single tyranid down to the last fleshborer worm. And none of the factions have remotely enough firepower to do so.
  • Then, there's the fact that Imperial tacticians are utterly confused about how in the blazes massive Tyranid forces are popping up all over the galaxy, often too closely together in time to account for what FTL speed they have. Then someone had the mother of all Oh, Crap! moments: they'd been plotting everything out on, essentially, a 2D map of the galaxy, assuming they were coming in from the edge. The Tyranid fleet was coming up from beneath. Dunnnn dun...
  • Another less known theory, is that the Tyranids and their Hive Mind are either the creation of, or the Old Ones themselves, returned. There's a subtle hint in the 5th edition Tyranid codex, where one of the race's pseudonyms is "the Penance of the Old Gods". Think about it. The Old Ones were an all-powerful race of immortal, psychic demigods who ruled the Milky Way galaxy eons before the rise of the other races. They created the Eldar and the Krork (the Ork's precursors) as weapons to help fight against the Necrontyr and their C'tan masters during the War in Heaven. After they lost the fight to the C'tan, and the emergence of the Enslaver Plague, they simply disappeared. Nowhere is it specifically stated that they went extinct, more like that they abandoned the galaxy. And nowhere does it state that they were a benevolent race. This being 40k, one could argue that they dabbled in creating new life forms irrespective of the danger they might pose. Both the Eldar and the Orks are flawed creations, made flesh simply as a last ditched effort in spawning weapons capable of using the tremendous nascent forces of the Warp in order to defeat the C'tan. The Eldar's flaw being that despite their wisdom and mastery over psychic power, they were creatures slaved more to their emotion than to their intellect and reason. And we all know what this lead to. Meanwhile the Orks have even MORE psychic potential than the Eldar, but not even a fraction of their control over it, yet they are the most successful survivors in the galaxy. So the Elder Ones definitely have the power to create new lifeforms, and are beings who operate on cold-blooded logic and reason, with the power to shape worlds and races. If they reason they could create another survivor race of warrior creatures with complete immunity to Warp corruption, in order to wipe the Milky Way galaxy of life so the C'tan and the Chaos Gods would be starved of sustenance and they could return to a wiped slate to start over, there is no reason why they wouldn't just go for it. In short, the Tyranids could be either another of the Old Ones' creations (under their direct control — or successful rebels who finally wiped them out) or the Old Ones themselves, voluntarily mutated into an apex superorganism — the pinnacle of evolution, returned with a vengeance to "fix" their past mistakes by assimilating every living thing in the galaxy.
  • No love for the Swarmlord? The thing is the oldest and most ultimate weapon of the Tyranid species, used only in desperate situations where a hive's normal tactics fail, making it capable of transferring between hive fleets just because it's THAT old. The Swarmlord's mere presence is able to turn the tide of battle for the hive fleet it joins. This thing is the SMARTEST TYRANID EVER MET, meaning that this thing can out-think practically anything it meets and capable of acting independently from the Hive Mind. It also has four specialized boneswords which it uses at such blinding speed that it can effectively parry every single move you make without fail, and then use it to tear through any armor you put up like tissue paper. And if you get lucky and kill it? It'll just come back, just as deadly, knowing everything that just happened before you killed it and ready to enact hideous revenge!
    • Face it. What makes the Swarmlord so scary is not that it's an enormous psychic abomination capable of shredding tank armour to ribbons, or that it's a highly intelligent individual in a species defined by being mindless warrior-drones of varying sizes. It's the fact that it's basically the Tyranid Ursarkar E. Creed.
  • Genestealers are scary-looking enough when they are purestrain but as they become more and more hybridised they become even creepier as they take on human traits and eventually become a perfect hybrid of unfeeling alien and charismatic human. And then you consider how they breed as revealed in the novel Deathwatch by Steve Parker. Genestealers need to get human genes from somewhere, so they have their cultists abduct women and then get new Genestealers through two methods. If they want purestrains then an already existing purestrain uses its tongue to infect the woman with a genetic packet of Tyranid DNA that will cause a brood of Genestealers to grow in them. After a horrifically painful pregnancy, all the while they are sealed in the Genestealer hive and fed nutrients through bio-tubes that go into their mouth, stomach and possibly other lower places, the baby Genestealers tear their way out of the women, exactly where they tear their way out of isn't specified, and devour every last scrap of their mother. But if they want hybrids, it may actually be worse. They hypnotise the women into submission and have their hybrids rape them, impregnating them with future generations of Genestealers that will appear to be normal children who will hold their mother in complete thralldom and use them to breed more and more generations until finally they die.
    • The above is merely one writer's idea and may not be canon, but the version given in the codices is hardly much better. In this case, hypnotism and one Genestealer's kiss later, the victim suffers a period of Laser-Guided Amnesia that removes their memory of being attacked, followed by subservience to the Genestealers and eventually an overwhelming desire to breed. Once they eventually track down a potential mate and impregnate them/get pregnant, the resulting pregnancy ends with the birth of horribly misshapen Mix-and-Match Critters yet the parents are hypnotised into seeing them as beautiful perfect babies. This process then repeats itself over the course of several generations, with more and more people being drawn into the cult and more and more new Genestealers being born, until they have the numbers to rival a small Imperial Guard regiment and beyond.
    • And Genestealers aren't a cakewalk in combat either. They don't have any ranged weaponry, but they strike from the shadows with sharp claws. How sharp? An Adeptus Astartes in full-on Terminator armor is nothing but a walking minced tuna can to one of these things if they catch them off-guard.
    • How do you make Genestealers even creepier? Some sources suggest that even purestrain Genestealers may actually be capable of legitimately human feelings, thoughts and personalities — but everything that makes them a "person" under their monstrous mien is scrubbed clean by the Hive Mind as it exerts control. In the novella "Deathstorm", the antagonist is a Genestealer broodlord and cult patriarch who is desperately hunting down its fully human "half-brother", the planet's governor Augustus Flax, to the extent of actively resisting total subsumption into the Hive Mind until it can achieve its goal of finding him and killing him. Why? Because it's still human enough to mourn its parents, murdered by Augustus to prevent them from putting their changeling spawn on the planet's throne, and it wants revenge.
  • Because of the combined nature of the Tyranid's Hive Mind and Shadow in the Warp, they are one of the few races in the galaxy (alongside the Necrons and Tau) that Chaos absolutely cannot touch.
    • Which makes the implication that they're fleeing even worse. If the forces of Chaos, in all their reality warping, bloodthirsty, plague-bearing, manipulating, mutating, mind-body-and-soul raping horror aren't a threat to the Tyranids, then what the hell is?
  • There's also the utter Alien-ness of the Tyranids; all of the other races in the game can have their origins tied to another faction, and ultimately to Chaos and the War in the Heavens. The Tyranids are completely out of context from everything else. They're a constant reminder that no matter how crappy the galaxy can get, all of the conflicts are a drop in the bucket the moment you step out of the eastern fringe.
  • Sometimes there are planets that even Tyranids won't go near. Good news... We probably know exactly what they are. Bad news... See the Necrons folder below.
  • One of the possible reasons for the Tyranids entering the Milky Way is that they're fleeing from something. What could possibly be terrifying enough for the Tyranids to run from it, and what if it's FOLLOWING THEM INTO THE GALAXY?
  • The price of holding back (or just delaying) a tyranid invasion. Inquisitor Kryptmann condemned hundreds of worlds to the flames of exterminatus just so their biomass could not be used to fortify the already huge fleets of Leviathan, while it's implied that the virus bombs, horrific chemical agents that liquidfies flesh in an instant planet-wide, were brought out from storage just to face the Tyranids. The last time they were used? By the Traitors of the Horus Heresy. And these only delayed Leviathan, it did nothing to deter it.
  • Genestealer Cults. Probably the most unsettling aspect of the Tyranid's invasion is that unlike the average Bug War enemies, they're smart enough to use subversion to undermine the Imperium and even to some extent the Tau. Not much is known about the latter, but with humans, they'll give birth to partly genestealer children who see their children as messianic, then install a cult devoted to their new Gods. The cult might use anything to slowly infest the population, from creating a myth to lure people in (as seen in The Valgaast Train by David Annandale) to masquerading as devotees to the Emperor. Then, once the Hive Fleet has come to consume the planet, the truth is revealed: There is no ultimate heaven or salvation, no liberation or freedom. All that awaits when the Hive Fleet comes is death and assimilation; many cultists die in absolute terror as the Hive Fleet, no longer needing to keep up the charade, drops it's mental link and the afflicted souls understand the full weight of what they had done. Some of its cultists are then consumed by the very father they worshiped and the very children they raised. Worse still, they do this in the hopes that some of the cultists would be so terrified that they would flee to new worlds, carrying the taint with them so the cult may spread further.
    • So, you've got your battle plan ready? Hive Fleet's coming, it's gonna be the fight of your life, but you've got everyone cocked, locked and ready to rock, right? You sure? The Feral World of Lamarno practically handed itself over to the Hive thanks to a completely unnoticed Genestealer cult called the Celebrants of Nihilism. When the bugs arrived, three-quarters of the planet's population marched calmly to the bio-ships to be consumed by their "living gods." *shudder*
    • Just to stoke the Paranoia Fuel a little more, the new codex introduces the Biophagus. Their role? Combined medic and bio-scientist, in the aid of spreading the Genestealer virus. To the extent, they don't even need The Kiss anymore. All it takes is the right tweaks made to a hive's water supply, a few alterations to a planet's meat imports, and eventually, inexorably, and without any fuss whatsoever...
  • To sum it up, in the words of one poor Tech-Priest before he was overrun during the first contact with the Tyranids on Tyran;
    We cannot live through this. Mankind cannot live through this. In a single day they have covered the surface of this planet with a flood of living blades and needle-fanged mouths. Kill one and ten take its place. If they are truly without number then our race is doomed to a violent death before every shred of our civilization is scoured away by a force more voracious than the fires of hell themselves! Death! By the Machine God, Death is here!
  • The Tyranids are so psychically powerful and so interchangeable that they function, basically, as a single absolutely enormous organism. It's like a termite colony fifty billion light years wide. For the Tyranids, going into the Milky Way and fighting off the most badass, overpowered, terrifying, divine, well-armed, devoted warriors in the galaxy is probably just like getting a mild case of food poisoning from a tasty leg of chicken.
  • And, as if all this wasn't bad enough that there's a swarm of interstellar locusts the size of the galaxy descending on us, an increasing number of hints and inferences point to the fact that there's something drawing the Tyranids in: the Astronomican. You know, the giant beacon of psychic light, powered by the Emperor's immeasurable energies (and the souls of thousands of psykers a month) that is the only thing that lets mankind travel the Warp with any sense of direction at all? To the Tyranids, that thing's one great big neon "FREE BUFFET" sign.
  • Yeah, sure, you can kill twenty thousand Hormagants with an artillery strike, but seconds later another forty thousand charge forward to fill the gap, leaving no sign that there was ever a gap in the lines. With other races, that would cause a lot of screaming, and panic, and maybe a mutiny or two. The Tyranids just fill the gap without even pausing. They've actually stopped artillery assaults by having Termagants leap into the barrels to clog them with their bodies.Yeah.

  • The Eldar, creepy beautiful aliens in thrall to the god of lust, which they created by accident after their galaxy-spanning empire became too hedonistic. Fortunately, most of the survivors are really sorry about it and have learned their lesson, so they only kill people when it becomes necessary, as opposed to when it becomes fun. However, they also ritualistically cultivate multiple personality disorder of a sort to keep from being traumatized in battle, so when they go to war, they're so driven by cold rage and blood lust that they seem on the brink of sanity. They also use very, very nasty weapons. I say "most" because there's the creepier versions that are still all about the murder-orgies and largely consider the destruction of their empire and 99% of their species a slight inconvenience in that they now have to hide in a pocket dimension to get away from the thirsting maw of the god they created.
    • While we're on the topic of cultivating multiple personalities, Exarchs have dropped this and don't care about anything other than their aspect of war. So they tend to their shrines, dedicated to training their warriors and nothing but combat. They've effectively made it so that they've completely lost their old personalities (and whatever they liked doing, sculpting, cooking, whatever) and only want to kill stuff. Or perfect combat. They're also willing ritualistic sacrifices for the Avatar thus becoming the Young King/Queen, which is done by walking into a literal furnace of holy fire (after having bloody runes of Aspect warriors carved into their skin and given a cup filled to the brim of their own blood.) What happens afterward isn't detailed explicitly, but after that they have effectively become one with the Avatar and exist only to kill.
    • Becoming an Exarch means merging your mind with those who came before you whose souls have fused into the armor. Normally this simply means you can commune with them and learn of their experiences. The tragedy is that since all exarchs are destined to join in their particular suit, you won't ever see any of your friends ever again (as they will join the infinity circuit instead). What's horrifying are those chosen to resurrect the Phoenix Lords; Phoenix Lords are the progenitors of their Aspect, and their Exarch suits are impossibly old. Because of their sheer will, a Phoenix Lord's personality will completely dominate that of its current wearer, which is how the Phoenix Lord reincarnates. This effectively destroys the wearer as an individual, his memories only useful to the Phoenix Lord as a warning against any recent dangers.
    • Several Phoenix Lords have been lost and the Eldar do not know where they are, such as the Phoenix Lord of the Shining Spears or Warp Spiders. Unlike other suits, they would have overridden the personalities of all other eldar whose souls have been absorbed into the suit, leaving them truly alone in their suits until someone dons them again. And given that it's theorized these lords fell in combat on worlds that were never documented (or worse, have long since been destroyed), they might never be free of this isolation.
  • The Eldar can A. see into the future and B. place no value on the lives of other species. This means that if the only way to prevent the death of a single Eldar is to turn an entire world of humans into molten slag, they won't even hesitate to do it.
  • Also, think about Slaanesh's origin story very carefully: the Eldar actually SQUICK-ORGIED A GOD INTO EXISTENCE.
  • The monofilament guns the Eldar use, the quite fittingly named deathspinners, shoot several tiny monomolecular-edged cords through the target and then whip around really fast, turning the insides of the target into shredded organ goo.
    • The Biel-Tan craftworld have developed the Void Spinner, an artillery weapon which fires a cloud of the aforementioned monofilament wire onto the enemy, combined with a barrage of bacteria and wraithbone parasites that scours all life from the target area as they are killed by the slicing threads and are broken down on a molecular level, with everything from flesh to bones and rock and metal becoming nothing but goo. It was developed exclusively to remove all presence of the filthy lower races who dare to taint the world the Biel-Tan are reclaiming, though they mostly just use them against Orks which is actually a pretty smart tactic because it ensures more orcs wont be spored from the dead.
  • Biel-tan itself is terrifying enough. Imagine one of the largest Craftworlds is run by and largely populated by the aforementioned Exarchs. A council of them that is continually launching xenocidal crusades against humanity to rebuild the shattered Eldar empire. They see you and your town as a rat nest, they will wipe you out and they will feel not even a shred of remorse or pity over it, because they psychologically can't feel that anymore.
  • Warp Spiders. They are able to teleport in and out of the Warp to evade danger. The bad part? Whenever they teleport, they stand a very good chance of NOT REAPPEARING, caught in the Warp by anything that is there. For this reason, they are regarded with equal parts fear, respect, and bewilderment.
  • Also, they are not really that beautiful to humans. Consider that they're about 7-plus feet tall on average, with a build so slim that the human equivalent would be considered malnourished or anorexic. Then there's the fact that they move so quickly that normal humans to them seem to be moving in slow motion. Add on the general disdain for other races (disdain if you're lucky, genocidal hatred if you're not), the natural affinity for psychic powers, and you basically have The Fair Folk with monomolecular blades and Razor Floss guns.
  • And while we're on the note of the Eldar, the Harlequins are the folks that even the Dark Eldar don't mess with. They're circus performers in colourful armour who put on amazing, psychically-enhanced theatre of the legends and history of the Eldar race, and in battle they have weapons that are brutal even by the setting's standards, such as a razor wire that liquifies your insides (called the "Harlequin's Kiss). The weird thing is that as guardians of the Black Library and foes of Chaos, they're relatively good guys by Warhammer standards.
    • Their rictus masks and holosuits are grotesque, constantly shimmering and in motion, garish and baroque to many extremes. Death Jesters are another example, and in addition to wielding heavy weapons they can load their aptly-named Shrieker Cannons with viral shuriken ammo that causes enemies to explode into many pieces, showering their allies with gore. They also love Death by Irony attacks, like causing a Daemon to tumble into its own death machine.
    • Solitaires are Harlequins that have the responsibility to play Slaanesh in their dramas. Doing so damns them, irrevocably, to Slaanesh when they die. Other Eldar are afraid to even speak to them, to the point they will commit suicide rather than live for whatever terrible fate awaits them if they accidentally touch or speak to one.
    • The Harlequins are devout and enigmatic of Cegorach, the Eldar God of trickery and humor, but if you consider what a cruel an inhuman species like the Eldar would consider "funny", that alone is terrifying to think.
  • Even killing an Eldar will not remove it from this plane—as long as its spirit stone remains intact, it can be "repurposed" to further the Eldar's ends—the spirit stone is implanted into wraithbone, whether in a wraithguard or wraithlord (the Eldar's answer to a Dreadnought) or in the core of their Craftworld. A wraithguard/lord's soul experiences life as a dream.
    • The end game of this is to gather enough souls to incarnate Ynnead, the Eldar God of the Dead and the Eldar's last, best hope to free them from Slaanesh. The only problem with this is that "enough" in this case means every single Eldar soul.
  • Let's talk about spirit stones, shall we? Why do they need them? Well, they keep the soul of the wearer in stasis for them to be claimed by the living. They need to do this because if the soul is left to go to the Warp, Slaanesh is right there waiting for them. We're not explicitly told exactly what Slaanesh does to an Eldar soul if he gets his mitts on one, but consider that a) Eldar are scared to even refer to him by name b) the whole stoicism thing is in place to prevent attracting his attention and c) they are willing to manipulate whole civilizations into slaughtering each other to save the lives of small handfuls of their own kind, and are also willing to mount Suicide Missions to recover spirit stones rather than risk them being damaged. Whatever fate awaits a soul claimed by Slaanesh, if the living Eldar are so unbelievably desperate to avoid it, it must be unspeakably horrible.
    • The Eldar used to have a whole pantheon of Gods. When Slaanesh was born, he killed all but three of them. He tried to claim two of those survivors as his divine pleasure slaves before Khorne and Nurgle intervened. If this is what he can do with gods, it's probably best we never learn what he does with mortals.
  • The Eldar are a Dying Race. They will die out, and soon (by galactic standards anyway), and there is nothing they can do to stop it. They know this and yet will continue to sacrifice billions of others to save themselves, purely out of fear and desperation, to delay the inevitable. Birthing Ynnead isn't some great plan of theirs, it's what they desperately hope will happen, because the alternative is too terrible to consider.
  • Though their true numbers are unknown, recent events have put their long-held Dying Race status into question. There are suggestions that the Aeldari may be slowly recovering to a ghost of their former power. Imperium policy towards the Aeldari is ignore them while greater and less reasonable threats are assailing the Imperium from all sides, but the implications of a race of hyper-advanced xenophobes who see humans as arrogant upstarts who usurped their place as masters of the galaxy (that's at best; at worst, the Aeldari see humans as nothing more than particularly well-armed vermin) potentially being on the up should give the High Lords of Terra some pause for concern.

    Dark Eldar 
That's not a human soul... it's xenos. Someone... someone tore out their souls and put something else in there.
Nisryus, Bleeding Chalice
  • A race that literally feeds on the suffering of others, for whom torture victims are the only currency, and who have raised the art of inflicting pain to supernatural levels, the Dark Eldar have a strong case to be the most nightmarish faction in the franchise.
  • You know what we said about the Eldar being sorry about creating Slaanesh and learning their lesson? The Dark Eldar are the ones who didn't. They're the descendants of the Eldar whose depravity literally tore open a hole in reality, and have pretty much continued on business as usual for more than ten thousand years.
    • If only. They're actually the ones who built a secret lair inside the Webway because their little games were TOO SICK for their brethren.
    • They think rape is a fun pastime (and those are the nicer ones).
    • When the Dark Eldar codex first came out, some people thought that at least this faction has a sympathetic motive, they have to be evil to protect their souls from eternal damnation (literal). While there is no first-person depictions of Commoragh before the Fall, later lore strongly suggests that it was a large and well-known hive of scum and villainy. They were pirates and slave traders even before the appearance of She-Who-Thirst.
    • It's been explicitly stated that they don't have to continue torturing others to survive. All they have to do is give up their depraved pleasures and take up the same discipline as their Craftworld and Exodite cousins, and Slaaneesh will lose his/her grip on their souls. In fact, every so often a Dark Eldar actually does this, and some even end up on the Craftworlds.
  • The Talos. A robotic mecha shaped like a scorpion that works by seizing victims on the battlefield, stuffing them inside itself, and torturing them to death, powered and motivated by their dying agonies.
  • Dark Eldar equipment includes poisons designed to kill you from pure pain, weapons that shoot the ghosts of insane tortured slaves at you, and guns designed to cripple not kill (cripple from pain as opposed to any actual physical damage, although that happens too) with shrapnel splinters, so they can take you alive.
  • Worst of them are the Haemonculi: Think Josef Mengele and co. - AS DARK ELVES IN SPACE! They go into battle with ultrahorrible poisons (often disablingly painful but nonlethal) to get experimental material. And however they rearrange your anatomy (in at least one case including YOUR ORGANS HANGING SEPARATELY AND ONLY CONNECTED BY VEINS AND NERVES), you can't even pass out. Hobbies for them include creating freakshow Dark Eldar 'grotesques' who are driven beyond even these torturer's ability to cause pain, just so they can be unleashed on enemies.
    • There's a story of a hive world that slighted the Dark Eldar. In response, a Haemonculus and his coven descended upon the planet. Five years later, Imperium forces discovered the whole place was utterly deserted. Every man, every woman, every child. Gone. Not one drop of blood was spilled. Not one shot was fired. Every single person who lived there just … disappeared. And we never learn how.
    • There is another story about how the 121st Cadian Elite, famed across the Ultima Segmentum as "Eldar Killers", suddenly went missing during a campaign for Massgrave. An entire batallion gone AWOL without a single message. Weeks later the men were found... walking around Commorragh's vault district, headless and armless but still lurching around, moaning and wordlessly pleading to be killed.
  • The Dark Eldar only care to obtain spoils of war, i.e. slaves, experimental subjects, etc. From their perspective, "DEATH IS A GIFT"!
  • Anything out of the new Dark Eldar Book is filled with this, from abilities gained from pain to having biological wings stuck on you and your bones hollowed out. However special mention goes to the Wracks and Grotesques, who are malformed, grotesque beasts made to be the servants and bodyguard of the haemonculus. The worst part? Wracks are made into these willingly.
  • And the reason they do all this? Remember what we said about them being just like the Eldar that manifested Slaanesh? They only escaped the fates of the other Eldar because they were off partying in their own little pleasure-verses. Slaanesh very much wants to finish devouring their souls, and they can still feel his pull on them. Their only recourse is to replenish themselves with regular doses of the suffering of others, and hurl the souls of their victims to Slaanesh in their place.
  • The new fluff states that they get an intense high off causing pain to other sentients. Given that they already have next to no self-control when it comes to their own pleasures and vices, but they actively go out and hurt as many people as possible. Given that they have the ability to resurrect themselves with their technology, battles that humans consider as life or death are just another form of orgy for the Dark Eldar.
  • They also have a nifty device called the Crucible of Malediction. It's a little cube that contains the insane, screaming ghosts of psykers that the foul Dark Eldar have tortured to death. When opened, the spirits fly out and unleash a psychic drone that other psykers can sense, and it can drive them insane also or even kill them if their mental defences are too weak for the assault. Naturally, Farseers and other Aeldari psykers are prime targets for the manufacture of Crucibles.
  • Check out this paragraph on how the Dark Eldar bring members of their race Back from the Dead:
    As a cacophony of shrieks rises and falls around the chamber, those installed in the cocoons above slowly feast upon the resonant energies, ever so gradually growing back their bodies - skeleton first, then muscle and sinew, then alabaster skin until they are whole once more. During times of war, it is common for every one of an oubliette's regeneration pods to be filled with leering, red-raw fiends that shiver and rattle with every fresh scream.
  • The Dark Eldar are old. So much so, they use a mysterious technology to appear young and beautiful. Psykers and Daemons can see through this however, and see them for what they really are: shambling monsters, that would make a zombie feel good about how he looks.
  • For those Dark Eldar too poor to afford their own souls to drain, there are the Wytch Cults, visions of sadomasochistic hate that conduct "performances" of elegant torture to a paying audience, trained lifetimes over in the precise infliction and prolongation of pain. For the victims, they are Hell. For the poor of Comorragh, they are the barest scraps of sustenance thrown from the towers of the mighty.
  • Kheradruakh the Decapitator, the intensely creepy Mandrake champion.
    • Let's talk about Mandrakes while we're here. More specifically, their special talents for stealth: their skin absorbs light, making them effectively invisible to all conventional forms of visual detection, and they are able to manifest in any place where there is a shadow. I'll just let you think about that for a second.
    • No one knows what the Mandrakes are. It's theorized that they were once Dark Eldar at one point, but what happened to them to cause them to mutate into these things is unknown. Some think they gained their powers from the dead Eldar god Qah, others think they're some kind of Warp Daemon or worse, a blend of Eldar and Daemon. Whatever is the case even the Dark Eldar fear them and rarely refuse their requests, for those that are foolish enough to cross a mandrake finds out soon enough that there is no running from them so long as shadows exist. They also eat Chaos Daemons.
    • Kheradruakh has a collection of the skulls of his victims in his dimensional lair. He meticulously "grades" the flayed skulls and smashes the ones that are imperfect. Those that meet his standards, he placed in cubby holes all overlooking a single point in the centre of the lair. Kheradruakh can be so strict that he can claim only a single skull like in a decade of killing, and yet the enormous chamber is almost completely lined with the skulls. This was all part of a grand ritual that allowed Aelindrach, a realm of primal darkness to manifest within Commorragh, giving Kheradruakh, now revealed as the king of all Mandrakes, a kingdom to rule within the Dark City.
  • The Dark City of Commorragh. Calling it a "city" is a bit of a misnomer. Commorragh isn't continuous, but is instead composed of a series of smaller cities, ports, massive arenas, and various fortified niches within the Webway. In its entirety, Commoragh would dwarf the Imperium's biggest Hive Cities with ease and houses a population greater than an entire star system. This layout also means it's built entirely on Alien Geometries, never once conforming to anything resembling euclidean geometry. Every horrible thing the Dark Eldar do and then some is part of everyday life in Commorragh, since this is their capital. Yeah, all of the above points? They happen here constantly. And all this without getting into the horrible things from outside reality that reside here, such as wandering shadows that will slaughter the unwary...
    • To put the horrors of Commorragh into perspective: The Dark Eldar typically don't need any real kind of locks or security for their slave pens. After all, there's no way outside of the city unless one of the Dark Eldar takes you out themselves, and nearly anyone that finds a stray slave in the city is going to have far worse designs for it than their current masters have planned. If one isn't currently experiencing maximum pain, all they have to do is step outside, and someone will be right along to remedy that for them.
  • It turns out the Drukhari are quite fascinated by the Tyranids, the alien insect dinosaurs that are quite literally chewing through the galaxy at such frantic pace that they pose a threat to every other organic race, including the Craftworld Aeldari. And it is not because they do not measure the threat; on the contrary, one of the central points of their research is to find a way to bring those organisms with them into Commorragh without risking guiding a Hive Fleet in as well, because it would surely mark the end of their civilization. But, even knowing this danger, the Drukhari see an endless swarm that devours everything, kills everything, impossible to tame, who could very well be the doom of the galaxy, and realize this peril... and the conclusion they come to is "Great, more livestock!"
    • And what if it turns out they in fact can inflict torture and cruelty on an unfathomably vast alien mind with more shared bodies than all the humans and Orks in the galaxy put together? The possibility of that sends shivers down the spine.
    • Wych Cults see Tyranid bio-organisms as Worthy Opponents and use them as regular arena stock. Incorporating Tyranid claws and chitin into outfits and cocktail dresses is also apparently all the rage amongst the Drukhari upper-class. And then there's the Haemonculi using Genestealer parts in clients, and the newly "improved" clients suddenly developing an unhealthy obsession with getting more and more Tyranids parts sewn on (which is not at all ominous). Moreover, Urien Rakarth managed to capture a whole Tyranid-infested planet and brought it back to Commorragh's orbit for study, pondering what he can use the creatures for. To everyone else in the galaxy, the Tyranids are The Dreaded; to the Drukhari, they're like interesting butterflies to a giddy entomologist...
    • Granted that the Tyranids are eating the races the Drukharis usually enslave. And since torturing slaves is a biological necessity, otherwise the Drukhari lifeforce is sucked by Slaanesh until they die and are damned for Eternity, they are forced to deal with the Tyranids as a grim chore. However, the fact they chose to research if they can capture and torture them, instead to fighting them to protect their slave stocks, is pretty revealing about the Drukhari's one-track mentality.
  • Also, speaking of importing foreign races to Commorragh: the Drukharis see their way of life as the best in the universe, but are surprisingly open to members of other races who would like to follow them. Certainly, even in the WH 40 K setting, wanting to live as a Drukhari is considered an act of pure insanity. And among those who want it, they must also be able to survive inside Commorragh, with the added difficulty that they don’t have local networks to help them. To give an idea of the level of depravity and resistance that it takes to survive among the Dark Eldars without being one, the best known of these people is Fabius Bile, one of the most feared Chaos Space Marines. So integrating their Society is not within the reach of the first comer. But knowing that, even outside the Eldar race, there are still a handful of individuals capable of competing with the Drukharis in terms of sadism and malicious imagination can be quite disturbing in itself.

  • The Necrons, the ghosts of an entire, long-dead alien race inhabiting cybernetic bodies who intend to harvest every living soul for their gods. It becomes really creepy when you realize that literally any planet might have a Necron tomb hidden on it. They tend to appear from nowhere without warning. They sometimes kill everything, sometimes spare certain settlements or individuals. Always for a reason.
  • The gods of the Necrons, the C'tan. Originally immense beings that fed off stars, they eventually developed a taste for souls instead. One, the Nightbringer, managed to Mind Rape itself as death incarnate into nearly every living thing. Then there's the Outsider. The insane C'tan that's locked inside a Dyson Sphere. Oh, and how did it get that way? Giant Star God CANNIBALISM.
  • The scary parts are scarabs and wraiths. The former form a massive carpet of flying beetles which eat you alive, and the latter are like ghosts. And they come out of the walls. Flayed Ones look like nothing beside them.
  • Their weaponry flays off armor, clothing, skin, bone, and organs, one layer of molecules at a time.
  • The narrator of the Dawn of War games may be very hammy, but he did get one thing right: describing Necron technology as loathsome.
  • From Xenology.
    Unknown artificial artefact. Unlabeled. Structure is analogous to human hand. Compositional tests confirm metal alloy exterior comprises unknown alloys f... "The metal lives. The metal lives. The metal lives. THE METAL LIVES. THE METAL LIVES. THE METAL LIVES THE METAL LIVES THE METAL LIVES."
    "Then I beheld the master of this domain and I knew in that moment that I was doomed. Not to die, you understand, but to truly appreciate the insignificance of my being. The Machine God, you see? It's everywhere, it feeds on us. I saw my companions from Cthelmax fed to the machines, their bodies and souls reduced to their component atoms to feed the insatiable hunger of the Machine God (...) It feeds, young Adept! It feeds! If it has turned its attention our way once more then we are naught but food for the gods! Food for the gods!" - Adept Corteswain
  • The Orks - the most violent, belligerent, and brutal species in the galaxy - and the Eldar - possessing psychic might enough to hit the Necrons were it hurts - were both specifically designed to destroy the Necrons. They failed.
  • Another fun nugget is the fact that the Tyranids leave some worlds in their path completely untouched. Since this was mentioned in the Necron Codex, the implication seems to be that the 'nids actually back off from worlds with a Necron presence. Goodness knows what it is the Hive Mind senses as it approaches.
  • There are also Necron Flayed Ones - they wear human skins and obsessively hoard dismembered body parts because their god's death-curse gave them an insatiable hunger for flesh - and Necron Pariahs, Necrons created from humans. Who had no souls.
  • The new retcon puts a whole new spin on the Necrons, going from being tricked and mind controlled by the C'Tan to instead overthrowing them and imprisoning them in Necrodermis bodies. Rather than brainwashed drones, the Necrons are now Omnicidal Maniacs who enslaved their own gods.
    Finally, I guess the big one for Necrons that nobody really talks about is PTSD - they're all living with the absolutely colossal trauma of having been separated from the bodies their instincts are geared towards, and I think their every experience is overshadowed by that. Early on in Severed, when Obyron is riding the ark down to Doahht, you can see him fighting off a rising wave of horror at his physical condition; not having lungs, not having skin etc. I think the flayer curse might, potentially, be interpreted as an extreme expression of PTSD, as much as it's also, y'know, a curse left as the parting gift of a murdered god. I've been thinking a lot about that.
    • Worst: The Ghost Arks were design to carry necrontyr civilians who refused to be turned into soulless robots, there's a reason why Warriors scream when killed.
      • Even worse: Quite a bit of the Necron Warriors are converted Necrontyr children.
    • The most horrifying quotation about the Necrons applies to their treatment in both fluff:
    Inquisitor Hoth: That man is beset at all quarters by traitors, mutants and fiends is self-evident. But in truth none of these evils shall be our undoing. When the end comes it will be not at the hand of any mortal being of this or any other realm: death will come at the hands of the ancients, those who determined our fate aeons before we stood erect upon the holy ground of Terra and gazed up into the starry night.
    • And with army addition, the true Star Gods are back. All the C'tan shards of the same Star God feel each other and will do anything within their power to reunite and merge. The transcendent C'tan is such conglomerate consisting of hundreds normal shards. It is fully capable to go toe to toe with most powerful Greater Demons and regained most of its personality and intelligence as a Star God. Necrons keep them in what is essentially a Monolith sized Tesseract Labyrinth and yet this thing barely keeps them in check. While somehow Necrons are able to control Transcedent C'tan Shard on the battlefield for a short duration they only use them under the direst of occasions due to risk that they might escape. Yet some of them roam free seeking to revive the old self and bring vengeance on all who oppose them. It is believed that the Nightbringer on Pavonis and Deceiver on Uralan are the largest shards conglomerates yet encountered...Even worse the two most powerful and nightmarish C'tan are still whole and one of them is sleeping in the heart of the Imperium...
  • Some elaboration: the Void Dragon was shot with MULTIPLE blackstone fortresses, weapons designed to kill his kind, and all they did was force him into hibernation meaning he survived the sharding of his species and the Outsider, a being so nightmarish that men would kill themselves rather than fight it. A being so monstrous that it devoured so many of its own kind that their swirling personalities drove it insane and unlike his more powerful brother the Void Dragon, the outsiders prison is only self imposed.
  • One of the worst parts of fighting a Necron force is that no matter what you do, you can never be sure you even "killed" them. A Necron warrior falls, and before you can get close, its body fades away. It is whisked back to an unknown Necron location, gets repaired, comes back and kills you instead. Even if you do damage a Necron completely beyond repair, or it cannot be recovered, its self-destruct mechanism is designed to look very similar to the teleportation. Even if you wipe out a crowd of Necrons, you can never know for sure that they aren't coming back.
  • The current existence of the Necrons is terrifying in an existential way; the process that granted them the immortal bodies is said to have robbed them of their souls, but given the degeneration of the lesser "warriors" into mindless automatons, and the fact that the C'tans are beings wholly of the material universe (while souls are in the domain of the Warp), it's entirely possible that the "transference" sequence is closer to making an electronic imprint of the mind into a robot body rather than a transfer of consciousness. They may no longer be actual creatures, but little more than electronic programs running until the day their "hardware" dies. Think SOMA, but without a second consciousness being created.
  • Trazyn the Infinite is a collector that would put even the most obsessed and particular of their hobby to shame. While he is polite, formal and remarkably witty, dedicated to preserving artifacts of every stripe from every civilization to spare them from destruction, don't ever think for a second that he's a good guy. He will not only collect objects and artifacts for preservation and display in his continent-spanning private museum, he will collect living beings as well. He has been known to abduct entire regiments, convert them into hard-light and pose them in massive dioramas that recreate the galaxy's most legendary battles. And some of them are wide awake for it. One particularly unlucky Inquisitor successfully found the location of his collection, only to be complimented on having such refined taste for a human and "rewarded" with a rare Tesseract Labyrinth to escape from. Items from his collection include a Craftworld's Bonesinger choir, the head of Sebastian Thor, an Adeptus Custodes and a massive figure in baroque power armor that is rumored by some fans to be one of the two lost Primarchs. And if you kill him, then chances are high that you only killed one of his body doubles while the real Trazyn was busy looting whatever artifact or person he was looking for or simply caught his eye.
  • Nemesor Zhandrekh is a particularly cunning and honorable Necron Lord, considered to be one of the greatest military minds of the Necrontyr Empire. Every other part of his mind on the other hand, is hopelessly damaged by the passing eons. While he is an almost unrivalled tactician, he is so utterly divorced from reality that he still sees himself, his compatriots and even his enemies as flesh-and-blood Necrontyr, convinced that he's still fighting the successionist wars that ended millions of years ago. He is so delusional in fact, that he still insists on having a retinue of taste-testers to ensure that his "meals" are not poisoned, even though he and his race haven't had a functioning digestive system since the time of the dinosaurs. His Flavor Text shows that, prior to his decisive victory against an Ork WAAAGH!, he did not see Orks, but Necrontyr that have painted themselves green.

  • Yes, ok, they're the comic relief faction. But Orks are brutal. They love fighting, they only respect strength, and the only thought they have of any other sentient races is of how much of a fight they can put up when they inevitably come for them. What do you think this means for the civilians of the Imperium worlds they invade? What it means for the old and sick, the women and children? They are to be butchered without mercy, and the Orks love doing it. They'll get a quick death sure, but the Orks don't respond to reason or pleading. When civilians run from them, that's exactly what they want them to do as it adds to the sport. Space Marine has audio logs telling of how Orks kill civilians with utmost glee and laughter. And this is the faction that is played for laughs.
    • The entry below describes how terrifying Space Hulks are for the Imperium. Even Space Marines are wary of them, especially after the Blood Angels Chapter was almost wiped entirely after boarding one. Orks? They love them. Great method of transportation and some entertainment included! What can possibly more fun than hunting down Genestealers, Daemons and Chaos Space Marines while flying randomly through space? By Orks standards, only crashing said space hulk onto the planet below while screaming the whole way down.
  • The main reason Orks are funny is because we get to see their perspective, where their language is rendered as Cockney football jargon. In other works (like Ciaphas Cain), we see what the Imperium sees: gigantic, monstrous creatures in horrid, rusted armor, wielding weapons that shouldn't even work but still do, coming down in endless hordes. There's no reasoning with them - they don't even understand what you're saying. Orks don't speak Gothic. You plead for mercy, and they respond with animalistic bellows and the swing of a giant, cruel axe.
    • For some visual aid; here's a darker (and, it could be said, Imperial) view of the Orkz.
  • How about the fact that once they've invaded, you can't get rid of the Orks without exterminating all other life on the planet. Once you kill an Ork, it releases spores, which settle in the wilderness and, eventually, grow up into new Orks. You can beat back an Ork WAAAGH!, have the Imperial Guard and Space Marines move on to the next theater of war, and then, when you least expect it, a green tide of feral Orks come pouring out of the wilderness.
    • Some people in the Imperium actually think of it as a benefit since worlds with feral Orks population tend to have competent and somewhat experienced PDF or Astra Militarum regiments. The same people that may actually have resources to infest planets with Ork spores.
    • It's worse than just feral Orks. Think: if you have managed to defeat an Ork invasion, that obviously means you gave them a good fight. And other Orks will feel it. And will want a piece of the action. And there are a lot of them.
  • If you think Orks are simple-minded killing machines that know only brute force, then you're mostly right. The exception to this are Ork Kommandos, who have learned the benefits of stealth, subterfuge, guerilla tactics and espionage. Some of them can even read. All traits considered "un-Orky" by the rest of their kind. And the rest of humanity. One quote describes a group of Guardsmen being executed for cowardice and incompetence for reporting sightings of these unusual assassins.
    • Boss Snikrot is the most infamous of all Kommandos, stalking the equatorial jungles of Armageddon. Possessed of a high level of cunning even by human standards, he leads the Red Skull Kommandos on devastating sneak attacks against the Imperium, leaving behind only ruins and scalped corpses to intimidate his foes. So terrifyingly effective are his tactics that Snikrot has become the official bogeyman of Armageddon, to the extent that mothers will tell horror stories about him to scare their children into obedience. And every tale has a grain of truth to them.
  • Red makes a trukk go faster! Shootaz are lumps of junk that only work when they use them! Why? Because Orks have reality warping powers that work on the principle of Clap Your Hands If You Believe! It's hysterical! Except that this means Orks can form a terrifyingly effective fighting force out of almost nothing. Whole Ork armies, from their firearms to their spaceships, are essentially cobbled together scrap, and they are incredibly fast in building it. Coupled with the spores they exude also growing food and beasts of burden near them, and you have an army where even the weakest member is Made of Iron, with no logistics requirements, that can outfit a battalion with your cast-off rubbish.
    • For an idea of what this means for the average Guardsman, there is a story of a Guard patrol that was pinned down for a couple of hours by an Ork with a Big Shoota, the Ork equivalent of a heavy machine gun (which being Orky is made from scrap, has a smoothbore barrel and fires slugs the size of a golf ball). When they finally killed it they were able to inspect the weapon and were surprised to find it had an ass-backward firing mechanism and no trigger. How are you supposed to fight something like that?
    • What's even scarier is that this not only applies to rubbish and junk, but functioning technology. If an Ork can capture it, an Ork can—and will—reverse-engineer it in ways that defy all common sense and logic, yet work to a terrifying degree. The idea of an Ork raiding party attacking a Forge World with a Titan Manufactorum is Nightmare Fuel with any Imperial Guard or Space Marine who knows what Orks can do with captured technology. This is in fact why repelling the Waaagh! in Warhammer 40,000: Space Marine is so crucial: said world they are invading is one of the worlds that can produce Titans.
    • An Ork's ingenuity is practically unlimited. They have been known to convert tanks, Titans, starships, asteroids, planets and even Avatars of Khaine into war machines. And if a Mek Boy runs out of nails, nuts or bolts to assemble them? Not a problem at all - they'll just grab the nearest Gretchin and crush them to death between two sheets of metal, using their pulped corpse as an adhesive.
  • What's scarier than an Ork that raise an army for fun? How about an Ork that has a plan? That has the smarts to unite the Orks and could probably conquer the whole galaxy if he mustered the numbers? Scary thought, eh? Meet Warlord Ghazhkull Mag Uruk Thraka.
    • There was once one Ork Warboss who actually succeeded in uniting the entire Orkoid race under his banner. His name has long since been lost to history, and now he's only known as "The Beast". Now, Ghazghkull is the size of a Space Marine Dreadnought and pretty intimidating enough, but from what little we know of The Beast, he would've made ol' Ghaz look like the runtiest Snotling in the galaxy. You see, The Beast, his Nobz were as big as Ghazghkull, and The Beast himself kicked them around for fun. The size of a hab-block and with tusks as thick as tree trunks, The Beast led the largest known WAAAGH! ever recorded a few millennia after the Horus Heresy and pretty much almost destroyed the Imperium. The Imperial Fists, the badass defence specialists of the Astartes, were completely wiped out trying to stop him. Stop him they did, but at truly horrific cost even for the Imperium's standards. And who knows, Ghaz might just do it all again...
    • Even worse when The Beast Arises series reveals Ghaz is the next coming of The Beast. The universe at large is in deep shit.
    • 1d4chan's "List of Accomplishments" for The Beast shows just how mighty his WAAAGH! was, and just why he himself was so terrifying:
  • Orks fight. That's it. That's all. And they love it. An Ork has no ambition, no goal, no dream beyond the next scuffle or skirmish or planetary invasion. Their entire society is geared around nothing but warfare, an endless cycle where they conquer more places to gather more loot to build more weapons to kill more people to conquer more places to gather more loot, ad infinitum. The only reason they haven't crushed the galaxy under their heel millennia ago is because they enjoy fighting each other more than they do anyone else.
  • One combined with the Tyranids above: Inquisitor Kryptman made a desperate gambit to save the Imperium, if only for a few years, by diverting Leviathan's attention away from the main Imperial forces by luring them to the Ork Octavian Empire, reasoning that at least one will wipe the other out. However, the Codex itself hinted that no matter who won, the winner will be greater than the sum of both armies; Orks get bigger and stronger whenever they defeat an enemy while Tyranids will be able to assimilate the Orks and all the positive genetic traits they possess. The Nids have already absorbed the reproductive trait of the Orks to produce the Biovores; one can only imagine what kind of horrors they can pump out if they absorbed the Ork's ability to get stronger as they fight. The Orks will, at the end of all this, fight through an enemy unlike any other, no doubt causing even the weakest among them to become larger and stronger than most Nobs. And then they will turn upon the Imperium once more.
    • 7th edition and Black Library novels bring news from Octarius Sector. Mentioned before, Ghazhkull Mag Uruk Thraka escaped Armageddon, shook off a Black Templar pursuit force and arrived at Octarius Sector, annihilating Tyranid vanguard forces. And the Overfiend of Octarius meanwhile looted an Eldar Avatar of Khaine that was separated from Eldar spirits, securing him on the Orks' side. Unlike the ones who fight for the Eldar, this one feels great, ripping apart Carnifexes and Bio-titans and actually buffing surrounding Orks, making them stronger, bigger and smarter. So, the good news is that stalemate continues. However, both adversaries may evolve to a point far beyond terrifying.
    • It bears mentioning, between the Orks and the Tyranids, the Tyranids winning is the best outcome for the Imperium. Whereas a Tyranid army might potentially be extremely effective at killing Orks after all this time and massively bloated besides, Orks don't adapt to their enemies like the Tyranids. They get bigger, they get stronger, they get smarter, and even more advanced. If the Orks win after all this fighting, there simply wouldn't be a weakness the way there would be with the Tyranids...
  • Please meet Gharkul Blackfang, an Ork Warboss encountered during the Great Crusade and a reminder of how potentially dangerous Orks can be. His empire was assaulted by 3 Astartes legions with Primarchs present. Gharkul forces had them on the verge of defeat, badly wounding Mortarion and pushing back Rogal Dorn and Horus Lupercal, to the point that the Emperor himself had to intervene. Emperor's flagship provided close fire support while 10 thousands Custodians and Emperor himself entered the fray breaking the tide. While that particular threat is long over, nothing really stops another such warboss from emerging. At the same time nothing 40k Imperium hasnote , would be able even to slow such threat down.
  • Another noteworthy warboss is Tuska the Daemon-Killa. He heard how tough daemons are and dreamed to match his strength against theirs. So he gathered the boyz, broke through the Cadian Gate into the Eye of Terror like it was nothing and assaulted one of the personal worlds of Daemon Prince of Khorne. All Cadian Gate defenses were just a speed bump for an ork WAAAGH! raised on a whim. Khorne was so impressed by him beating his servants that when Tuska and his boyz inevitably go down fighting endless hordes of daemons (they cannot be permanently killed in the Warp), they are revived to fight once more. You'd think it would get boring eventually, but no, Tuska is the happiest ork in the galaxy and his boyz are in their version of Valhalla.
"Told ya I knew where the best fightin' was."
  • In general, Warbosses are terrifying creatures to behold. Because of Ork physiology, only the most ruthless, powerful and cunning Orks get to be Warbosses, a process which also sees these orks grow to huge sizes. An Ork the size of an elephant with the brains to organize the ramshackle hordes of the Orks into something approaching an effective fighting force is a pretty scary thought. On top of that, most Warbosses invest heavily in cybernetics, often incorporating power klaws, massive shootas and other powerful weapons, often spewing smoke out of exhaust pipes. So, now imagine that elephant-sized Ork with the brains for strategy armed (sometimes quite literally) with enough firepower to destroy Imperial armored vehicles.
  • Gargants and Stompas. If Imperial Titans are veritable avatars of the Machine God to the Adeptus Mechanicus, then the ones that the Orks bash together out of steel, elbow grease and wishful thinking are the embodiment of Gork and Mork. Because the Orks see them as such. And they love it. So much so that the mere sight of a Stompa or Gargant waddling its way across the battlefield will drive the Orks into a killing frenzy that would put a Khorne Berzerker to shame.
    • Mega-Gargants are gigantic even by Titan standards. So much so that, even with the incredible amounts of WAAAGH! energy holding them together, they have to be build with massive treads instead of legs because they are just that heavy.
    • One Ork warboss sent a message to an Imperial hive world, demanding that they send him as many guns as they could muster. When the governor inevitably refuses his request, the warboss threatens to unleash the many, many Gargants he has under his command. The governor changes their mind, only for the boss to invade the planet anyway. Because he felt like it.
  • The Orks aren't a result of evolution from some ungodly hostile planet. The Old Ones genetically engineered them, intending them to be nigh-unstoppable killing machines who could turn the tide against the Necrons and C'tan. They succeeded.
  • What's even scarier is that Orks are not the original living weapons the Old Ones created. Those would be the Krorks, behemoths who made 40K Ork Nobs look like snotlings by comparison. The Krorks became the Orks because the decline of the Necrons and C'tan meant they no longer had powerful enough foes to fight. This means that if the fights in 40K intensify, there's a chance that the Orks might become Krorks again.
    • To give an idea how nightmarish the prospect of fighting the Krorks would be like, there is a moment in Fabius Bile: Clonelord where Bile visits Trazyn's collection and comes across a Krork in stasis in one of the exhibits. Said Krork is twelve meters tall. For comparison, the aforementioned Beast was only ten meters tall. Now imagine a WAAAGH! with Orks the size of Imperial Knights charging your way. Only a Titan Legion could stand a fighting chance, and even then who's to say that the Krorks would bring along proportionately sized vehicles to crush them?

    Tau & Allies 
  • To think the Tau are the closest thing to good guys! It's kind of a statement on the universe as a whole that the expansionist, genocidal, self-righteous, fascist maniacs, who in any other world would be considered raw evil, are part of the lesser evils just because of what's on the other side. Even when you take into account that Dawn of War hints at the Tau using concentration camps and sterilization on human worlds they conquer, "Join us or we'll kill you" is a lot nicer than "die heretic/xenos scum", even if a no-answer leads to a plasma round to the face. The existence of the Tau is scary in itself. They are basically practical people, with practical solutions (they are fully aware technology is just that, not some hocus-pocus magic spell, are fully able to use AI without fear and have developed a form of plasma weaponry that doesn't fry you, something only the eons-old Eldar have done). However they have just barely begun to explore the galaxy, and it's hinted that they'll eventually lead themselves into extinction because of their Greater Good ideology. That's right, in the 41st millennium common sense will get you killed.
  • For such an "enlightened, peace-loving race", the Tau have a habit of joining forces with some unpleasant fellows, such as the Kroot. Not only are they strong and fast enough to hold their own against creatures as large as Orks, but their entire culture revolves around devouring the corpses of their enemies so that they can evolve and eventually take on the characteristics of the things they eat. And this is just the Carnivore, their basic infantry.
    • Kroot Hounds are an evolved form of the Carnivore, and are the perfect definition of the term "bird-dog". Look up a picture of one of these things and just imagine it lunging for your throat, its teeth bared and its claws ready to rip open your stomach.
    • Krootox: the bigger, meaner, tougher type of Kroot. Looks just as frightening, if not more so. Comes equipped with a huge gun on its back that can take out light vehicles and turn infantry into ground beef. And it's rapid fire.
    • Greater Knarlocs are the Kroot equivalent of a T-Rex. This thing eats infantry by the bucketload and can even destroy enemy tanks. Again, pictures are worth more than words.
    • It can be argued that in the crapsack universe that 40k-verse is, a species whose members are "only" flesh-eating mercenaries is practically friendly. Kroot don't even come across as that scary in the Ciaphas Cain novels. The Kroot translator has a bit of a sense of humour and respects the skills of Sorel the Cold Sniper even though Sorel killed one of the other Kroot. And in Dawn of War, they seem to be a bit snarky, with lines like "Your flag is up. Now what?" They're not fluffy bunnies even by 40K standards, but they're not quite terrifying.
      • They aren't even that evil for a normal setting; while they do have a rigid exterior, the above mentioned incidents of evolution gone wrong show that not eating people would do far worse to them. In fact you could practically see them in an episode of TNG where they give the message to not judge a book by its cover.
    • Perhaps more terrifying is in the novel Kill Team where some Kroot invite the titular squad to join them for a meal, which they are eager to do since they have only been eating meat-free Tau food for a few weeks. It is only when they start to dig in that they realize from what animals that meat was taken. The shaper in charge then presents dessert, and implies that if one of them does not partake, the Kroot will be most offended and may be motivated to add them to their meat locker. Of course, the shaper turns out to be well aware of the human prohibition on eating the (unprocessed) flesh of their own. The Kroot definitely do have a sense of humor, and it is sick sense of humor indeed.
    • We would like to now remind you that the native fauna of Pech, the Kroot's homeworld, is pretty much all Kroot-based, because eventually, every species on that planet was eaten by the Kroot, and some of them got stuck in those forms and eventually took their place. That couldn't have been very nice, realizing that you and your clan are slowly regressing to a feral state, and unable to do anything about it.
      • It should also be mentioned about the time a Tyranid Splinter Fleet attacked Pech. The Kroot managed to fight them off and drove them into the jungles of their homeworld. Some time later, something in the jungles drove them out.
  • Though not as prominent as the Kroot, the Vespids are also pretty nasty. They're essentially giant flying bugs, but uglier and with more spikes. At close range, they attack by shredding their opponents into little pieces of flesh with claws that can cut through steel. Have fun imagining that.
    • Again, though, the Vespid are, by the standards of the series, pretty nice guys overall. They eagerly joined the Tau upon learning that the Greater Good was quite similar to their own beliefs, and their allegiance to the Tau is one of mutual faith and understanding, not the mercenary-employer relationship of the Kroot.
    • All Vespid Strain Leaders are equipped with translators call Communion Helms given to them by the Tau. Vespids are the only species in the Tau Empire that require such devices. They are also the species that most quickly and easily accepted integration into the Empire.
  • Warhammer 40k is a series that's full of big things with big guns that do big damage. But few of these weapons, soldiers or vehicles can go invisible. The XV15 Stealthsuit is fairly small by Warhammer 40k standards. It's barely bigger than the Fire Warrior piloting it. Yet it manages to become an absolute nightmare due to the simple fact that it has one of the most scarily effective stealth systems in the setting. Using light-bending technologies coupled with thermal signature dampeners and a sound-nullifying field, the XV15 is capable of hiding whilst being completely undetectable, only to uncloak and attack its foes and then vanish again before they can mount a counter-attack. Combine that with powerful Burst Cannons capable of tearing an Imperial Guardsman to pieces in mere seconds, and you've got a source of some pretty significant Paranoia Fuel. Oh, and then there's the XV25 Stealthsuit, which uses the same cloaking system as the XV15, only with more armor, more survival systems and the ability to use even larger Fusion Blasters that can completely sublimate a human being. And then there's the XV95 Ghostkeel, a stealthsuit that dwarfs most battle tanks with the weaponry and armor to match, sporting a specialized stealth field which makes it almost impossible for your eyes to focus on it. If you're in a vehicle you're no better off, as one arm mounts a potent ECM suite that will blind you until its close enough to unleash enough firepower to atomize you in a heartbeat.
  • The Tau's overall ignorance of the threat of Chaos can be considered both a blessing and a curse. On one hand it makes them extremely difficult for demonic forces to possess. However, on the rare occasions when they do run into warp entities things tends to go very badly for them. The most notable case being the Fourth Sphere Expansion Fleet, which unwittingly tore a hole in space time through the use of poorly reverse engineered Imperial warp technology. Most of the fleet was torn apart by the various demonic forces that inhabit the warp, with the survivors only being saved by a warp entity implied to have been formed by Tau's collective belief in the Greater Good. The Tau's response to this was to execute every alien auxiliary in the fleet, who they blamed for creating said warp entity. Since then Tau from the Fourth Fleet have been forbidden from serving alongside alien races, out of fear that they'll commit similar massacres. It remains to be seen just how badly the Tau will react to more malicious denizens of the warp, especially now that the Death Guard is poised to invade the heart of the Tau Empire through the newly opened Startide Nexus.
  • Continuing from that, the galaxy itself could be considered Nightmare Fuel to a Tau. Their empire preaches logic, reason, cooperation, and enlightenment, and advancement of the Tau empire for the Greater Good. And the greater galaxy... isn't like that. The other major powers are all extremely hostile and dangerous, and the galaxy and its inhabitants frequently act in ways that go against the laws of physics, reason, and the Greater Good, and succeed in spite of or maybe even because of it.

    Leagues of Votann 
  • While the Leagues of Votann aren't too bad at first glance, one thing stands out very quickly: They just don't give a damn. Your planet has resources that they want? They'll get them, one way or another. They'll strip your planet to the bone, and then harvest the bones if it means getting what they need. In the best-case scenario, you might get a warning and chance to evacuate. And when the Kin do decide to care, may the Ancestors help you if you've wronged them — They remember grudges, and will make absolute sure they are settled.
    • This is further emphasized by why they fight. The Imperium, Tau, and to a lesser degree Necrons fight for ideological reasons. Chaos and the Drukhari fight For the Evulz. The Aeldari and Genestealer Cults fight for survival. The Orks fight simply because they enjoy it. Tyranids fight because their instincts tell them to. But the Leagues? They’re not killing you because they consider you blasphemous, or are a threat, or even because they feel like it. They kill you because you’re between them and what they want, regardless of who you are. To them, your death is nothing but a business expense.
  • The reason behind their aforementioned expansion only makes things worse. The Leagues are not individually greedy. They need the resources to fuel their namesake, incomprehensibly old and powerful super A.I.s called Votanns. Now remember that the Men of Iron and their subsequent rebellion was enough to convince the Emperor and the Imperium to harshly ban all AI and opt for servitors instead. What could happen if these Votanns, much more powerful and already damaged A.I.s, decide to go rogue?
    • There is an argument to be made that the Votann won't go rogue - because, in a sense, they already have. From their birth in the Votann's cloneskeins, to their death when their bodies and minds are fed to it, the life of the Kin is dictated by their AI overlords. They lack any spirituality - not even a philosophy like that of the Greater Good - other than their reverence for the Votann, and, as mentioned above, their existence ultimately revolves around fueling them. The Kin do not question how the Votann came to be, or why they need to serve them: they accept the order of things as a self-evident Truth. In a way, the Leagues are a glimpse of what humanity could have been, had the Men of Iron won: a hollow, unchanging existence spent in eternal service to the machines.

    Miscellaneous alien races 
  • There's an obscure but extremely nightmarish Xeno race called the Slaugth. Each Slaugth is a mass of mucus-covered maggots in the shape of a ten foot tall humanoid. They are immortal, nigh-invincible, and capable of shapeshifting into a perfect mimic of a human as a disguise. John Carpenter's The Thing, basically. Like the Tyranids, the Slaugth are defined by their insatiable hunger for flesh. However, unlike the Tyranids, the Slaugth possess human-like sapience. In fact, they are very intelligent and are perfectly aware of how much suffering they cause. Put simply, they're pure evil. While any flesh will do, their favorite meal is brains. It's implied this is because they absorb their victim's knowledge.
  • The Hrud. Just the appearance of these Xenos alone is enough to be nightmare-inducing, and that's not even mentioning the time warping field they produce that ages everything around them.
  • The Umbra may just be the most alien of all the races found in the 41st millennium. It's basically a floating black sphere that can control shadows and use them as weapons. They also may or may not be the shattered fragments of a dead god.
  • The old Games Workshop website had a page on several deadly flora and fauna found in the galaxy, including a plant that grabs any animal that passes it, stuffs it inside itself, and then instantly digests them and turns them into seeds.
  • Everything on Catachan, since it's a Death World. Think Australia turned up to 11. There is the Catachan Barking Toad that nature saw fit to evolve a defense mechanism that essentially blows it up and kills all living things within a certain radius, when it's startled! Then there are the Catachan Devils, which are implied to be larger and angrier versions of Tyranid Trygons that evolved independently of the Hive Fleets.
  • There are also the Enslavers. They're a sentient race from the Warp that can take control of psykers in order to enter the physical world, then mind control non-psykers and destroy their minds to fuel their own power. One White Scar Astartes once recalls a battle on a planet besieged by the Enslavers, who marched one million Imperial Guardsmen across a 100-km wide minefield, straight into the meat grinder of bolter fire that the Space Marines on the other end laid down. And the Imperium knows almost nothing about them.
    • These creatures are so mind boggling powerful that they ended The War in Heaven. That's right, neither the Necrons or the Old Ones actually won their ancient war. They fought until the Enslavers came, then the Enslavers proceeded to wipe out nearly all sentient life in the galaxy, including the Old Ones, and starved the C'tan into hibernation (or rather, distracted them enough to be sharded by the Necrons and in the Flayer's case killed by the Necrons). Thankfully the Enslavers still encountered in the 41st appear weaker then those from 60 million years ago, though they remain terrifying threats.
  • Rak'Gol, pirate lizardfolk with fetish for cybernetics and more ramshackle technology than the Orks. They were introduced when they eradicated all sentient life in a dozen star systems that belonged to Imperium and minor Xenos empires, no successful communication was ever established with them and Deathwatch teams failed to capture and keep a single of them alive. Imperium considers them a minor annoyance......for now, anyway.
    • They use radiation-based death ray blasters in combat. Radiation, which causes mutation, which allows Tzeench to get his fingers into your pie.
  • The Psychneuein. Imagine a giant, super strong wasp-like creature that has the power to detect minds, use telekinesis, can become intangible at will, and who use psykers as hosts for their eggs. They can be found in the warp, the Webway, and at least two planets in real space. The Psychneuein infestation on Prospero almost led to the total collapse of civilization.
  • There exists a strange place on the edge of the galaxy known as the Ghoul Stars. The region is considered cursed and supernatural, filled with hundreds of dead worlds, and the ones that aren't dead are filled with things that probably should be dead. Bad things happen to anyone who pushes their luck there. Humans, Tyranids, and Necrons are just a few of the races which have fallen afoul of the Ghoul Stars and paid for it.
    • The Imperium genuinely believe the Ghoul Stars pose a threat to the entire galaxy. Most infamously, they spawned the Pale Wasting, an event as mysterious as it was devastating. Details about what exactly happened are scarce and appear contradictory, as the Inquisition were especially thorough in expunging the incident from the record. What is known is that whatever it was, it came from within the Ghoul Stars, and resulted in entire sectors of space being slaughtered. Twelve chapters of Adeptus Astartes were eventually sent in to quell the threat, and only one survived: the Novamarines, who were honored on Holy Terra with a monument in the Imperial Palace itself. So fearful are the Imperium of a resurgence in the Ghoul Stars, they have an entire chapter, the Death Specters, on constant watch for any sign of activity, with both a Deathwatch fortress and regular patrols by the notoriously brutal Carcharodons as an added insurance policy.
      • Recently, the Black Templars attempted a crusade on the Ghoul Stars. They managed to wipe out the Xeno footholds on the outer systems before going into their core systems to finish them off... and found nothing. Entire planets that should've been populous Xeno homeworlds completely empty. The Templars ended up being diverted to deal with the Third War for Armageddon, but there was apparently one Crusade still ongoing in the system... that the main chapter eventually completely lost contact with.
    • It's worth noting for a moment that none of this is do with Chaos either. Whatever dwells in the Ghoul Stars is something else, something different, and maybe even worse.