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[[quoteright:350:http://static.tvtropes.org/pmwiki/pub/images/chaos_star_and_gods_3205.jpg]]
[[caption-width-right:350:Clockwise, from top left: the symbols of Tzeentch, Khorne, Slaanesh and Nurgle. The eight-pointed star is the symbol of Chaos Undivided.]]

->''This is our galaxy. Ours to corrupt, ours to enslave. The gods will not be denied their prize.''

In ''TabletopGame/{{Warhammer 40000}}'', the Immaterium, or Warp, is a parallel dimension where the thoughts, desires, and emotions of sentient creatures are made manifest in the form of psychic entities labeled Daemons. There was a time in the distant past when the Warp was a calm and even benign place, but eons of constant warfare have corrupted it into a twisted mirror that accentuates the negative - the gods of Bravery, Hope, Acceptance, and Love are also the gods of Rage, Mutation, Decay, and Lust. The Warp is a realm of primordial Chaos, where the laws of nature and causality do not apply, where dark thoughts congeal and evolve into diabolical gods. It is a nightmare realm that occasionally [[NegativeSpaceWedgie spills forth]] into the Materium, leaving behind madness and desolation.

Humanity has an intimate relationship with Chaos - after all, their minds feed it. Chaos is the source of the mutation that wracks the Imperium, from inhuman monstrosities to the psychically-gifted Navigators. Chaos is [[HyperspaceIsAScaryPlace the key to interstellar travel]], as ships traveling through it move much faster than they would in a rational universe - assuming they are not lost to the storms and eddies of the Empyrean or devoured by daemons. And among humans, there are always those who turn to Chaos for various reasons: bored nobles looking for a new thrill by dabbling in the occult, radical daemonhunters hoping to turn the weapons of the enemy against him, ambitious individuals making [[DealWithTheDevil dark pacts]] in exchange for power, cults and cabals plotting to turn their homeworlds over to the dark gods, bitter souls and traitors seeking revenge, or {{Unwitting Pawn}}s who don't even know the names of the gods they worship. Regardless of their motivations, very few of them end up as anything more than {{Unwitting Pawn}}s to the dark gods' plans, and horrific death is an all too common fate. Even those who manage to draw the attention of one or more of the Chaos gods may be turned into monstrous abominations called Chaos Spawn, twisted and mutated by their "blessings" and driven insane. Those that don't suffer these fates, however...[[AscendedToAHigherPlaneOfExistence they can go up far]], becoming immortal and inhumanly powerful Daemon Princes.

Collectively, these followers are known as the Lost and the Damned: faithless traitors who have abandoned their humanity and forfeited their souls. Entire regiments of the Imperial Guard and whole Naval fleets have gone renegade, while disaffected mutants and abhumans sometimes turn to Chaos as well. But by far the worst Chaos threats are the Daemons themselves, and the heirs to a betrayal ten thousand years old that almost destroyed the human race...

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!!TROPES FOR THE TROPE GOD! EXAMPLES FOR THE EXAMPLE THRONE!

[[foldercontrol]]

[[folder:General Chaos Tropes]]

* AlienGeometries: Try not to look too hard at anything related to Chaos. [[BrownNote Bad idea.]] Their writing is generally described as "Sanity-Blasting Sigils."
* ArchEnemy: The Imperium actually calls Chaos the "Arch Enemy" or the "Great Enemy".
* ArtifactOfDeath: Most Daemon weapons lead to their owner's doom eventually.
* BadPowersBadPeople
* BerserkButton: Don't invoke the Emperor's name in the presence of a daemon or Chaos Space Marine. It won't end well.
* BetterToDieThanBeKilled: This pops up for people who fall victim to Chaos. Annihilating your soul is just one of the options available, and not even the worst at that.
* BigBad[=/=]BiggerBad: If something is causing the Imperium problems, it's usually Chaos. If it's not, they're just around the corner.
* {{Bizarrchitecture}}: Common on [[EldritchLocation daemon worlds]], where the laws of physics are literally just another building material.
* BlackMagic: As much as the Imperium would like to deny it, without Chaos it couldn't function. The Warp is the only means of faster-than-light travel available to humanity, and the Navigators that have the ability to guide vessels through the Warp can do this because of specific mutations created by Chaos.
* BrightIsNotGood: Followers of Slaanesh (Chaos god of hedonism and excess) are {{Sense Freak}}s who wear hideously garish clothing and choking perfumes at all times, being so blasť it's the only way they can feel anything. One Chaos Space Marine Legion devoted to Slaanesh wears pink and black armor for the same reason.
* BrownNote: Common side effects of looking at Chaos symbols are [[VomitIndiscretionShot mild nausea]], [[TearsOfBlood slight bleeding]], and [[GoMadFromTheRevelation insanity]].
* CardCarryingVillain: Anyone who's in deep with Chaos tends to wear this on their sleeve...or any other part of their body.
* ChronicBackstabbingDisorder: Chaos in general, but Tzeentch in particular.
* ColourCodedArmies: Red and brass/bronze for Khorne; blue, and to a lesser extent yellow and every other color for Tzeentch; sickly green for Nurgle; and purple and pink for Slaanesh. In addition, Malal was supposed to be black and white.
* TheCorruption: Both mental and physical.
* TheDarkSide: Which manages to be darker than what passes as the "Light" side in this setting, no mean feat.
* DealWithTheDevil: Pacts with Chaos in general, and to specific Chaos Gods in particular.
* DeathBySex: Slaanesh is ''very'' tempting...
* DreamLand: The Warp is an exceedingly negative version.
* DrunkOnTheDarkSide: Don't stand too close to anyone powered by Chaos.
* EldritchLocation / FisherKing:
** Anywhere in the Eye of Terror or any place sufficiently tainted by Chaos.
** The domains of the Chaos Gods are like this, especially the ever-changing Maze of Tzeentch.
* EvilTropes: There is a good reason Chaos is considered "the bad guys" in ''TabletopGame/{{Warhammer 40000}}''
** AsLongAsThereIsEvil: The only way to truly defeat Chaos would be to destroy all the intelligent life that feeds it. [[OmnicidalManiac The Necrons]] and Tyranids would like to make that happen
** ChaosIsEvil: Though technically speaking, everyone in the franchise is evil to a degree, Chaos really takes the cake. The Chaos Gods also embody positive emotions, but with the setting [[CrapsackWorld what it is]], these rarely get displayed.
** EvilIsDeathlyCold: The presence of Warp energy usually involves the temperature dropping several degrees.
** EvilIsHammy: In a [[WorldOfHam Galaxy of Ham]], Chaos stands out for particular [[ChewingTheScenery Scene Chewing]].
--->'''Sanguinius''': Are all of your kind so in love with the sound of your own voices?
** EvilIsVisceral: Very common, especially the "mismatched arrangement".
** EvilLaugh: Chaos specializes in this, as most Traitor Marines have turned batshit insane over ten thousand years of war and slaughter and the mind-warping effects of the Immaterium. ''VideoGame/DawnOfWar'' has Chaos Marines randomly break down and cackle occasionally. Subverted by the [[TheStoic Iron Warriors legion]] who seldom laughs, considering such displays beneath them.
** EvilSmellsBad:
*** Chaos itself is often described as having a "foul stench" reminiscent of rotten meat, or a kind of sickly-sweet smell, like over-rich sugars fermenting in a cloying way. The general effect is frequently nauseating.
*** Nurgle, his daemons, and his followers are particularly known for being foul-smelling due to the disease and rot that they breed and live in.
** EvilerThanThou: In-universe Chaos is considered the worst of the factions in terms of sheer depravity. Amongst the fandom, however, the Dark Eldar just ''slightly'' beat out Chaos.
** ForTheEvulz: Many followers of Chaos have actual hopes and ambitions, but [[MotiveDecay whether they'll keep them rather than being addicted to the horrors they inflict or driven insane from the gifts of Chaos is a different story...]]
** MadeOfEvil: Warp energy is inherently corrupting, and anyone not a Space Marine or Inquisitor exposed to it on a regular basis is killed for fear of spreading corruption. Even during the Great Crusade, before the existence of the Chaos Gods was known, the Legiones Astartes had standing orders from the Emperor to subject planets with Warp-taint to Exterminatus, and the Legiones Astartes were trained to recognize and combat psykers bloated with Warp madness.
** ReligionOfEvil: Chaos Undivided, formed by Lorgar, Primarch of the Word Bearers, who was chastised by the Emperor for spending so much time building cathedrals rather than campaigning. In response, Lorgar began worshiping the Chaos Gods as a pantheon, and today his legion is known for being darkly devout. Chaos Undivided holds that worshiping all the Chaos Gods allows one to draw the strengths of all without any of the weaknesses (Khorne's all-out hatred, Slaaneesh's need for sensation, Nurgle's corrupting influence, and Tzeentch's mutations). The fact that Chaos Undivided's greatest champion is [[GeneralFailure Abbadon]] makes this claim...questionable
* GenuineHumanHide:
** It's a popular source of clothing for Chaos followers, particularly Slaaneshi followers.
** Many a TomeOfEldritchLore is made from it.
** Last but not least, we at Wiki/TVTropes are contractually obligated to remind you that Chief Apothecary Fabius Bile of the Emperor's Children wears a lab coat made of ''human skin''. [[note]]Okay, we're not really required to remind you. We just enjoy [[NightmareFetishist spreading the horror]].[[/note]]
* HauntedTechnology: Chaos has a bad habit of corrupting, if not outright possessing, various bits of technology.
* HearingVoices: It's a good idea to ignore them.
* TheHedonist: Slaanesh and his/her followers are ultimately about seeking pleasureful sensations. This typically starts out with sex, torture, and/or murder, but inevitably degenerates into seeking out ''any'' sensation and learning to find it pleasurable and unique, up to and including [[InsaneTrollLogic fighting wars to see what losing is like]] and extreme self-mutilation as pleasure becomes confused with pain.
* HermeticMagic: Most warp-sorcery takes this form (usually involving {{Eldritch Location}}s, {{Geometric Magic}}s, and {{Human Sacrifice}}s,) in contrast to PsychicPowers which are the other major way of warp-driven [[RealityWarper reality manipulation]]. Combining the two approaches results in ExplosiveOverclocking, and some psykers may turn to sorcery to further empower themselves.
* InsaneEqualsViolent: Generally the case with Chaos-inspired madness, though in most cases those afflicted were already violent.
* TheLegionsOfHell: [[HumansAreBastards Fed by your every thought and emotion]].
* LimitedAdvancementOpportunities: Most mortal Chaos followers find themselves offered as human sacrifices, die in battle, succumb to mutations, or become mindless Chaos spawn.
** Averted with Nurgle. Mortal followers have the opportunity to become Plaguebearer demons, either by contracting Nurgle's Rot or taking part in the planet-encircling dance on Bubonicus.
* TheMadHatter: Occasionally seen as a symptom of corruption by Chaos, particularly by Tzeentch.
* MadnessMantra:
** BLOOD FOR THE BLOOD GOD!!! SKULLS FOR THE SKULL THRONE!!!
** MAIM! KILL! BURN! MAIM! KILL! BURN! etc. etc.
** In the spinoff game ''BattlefleetGothic'', an entire ''starship'' gets a MadnessMantra: the Chaos cruiser ''Killfrenzy'' is so named because, whenever it draws near, all that can be heard on every comms frequency is its captain endlessly screaming +++KILLFRENZY KILLFRENZY KILLFRENZY KILLFRENZY KILLFRENZY+++
** In the novel ''Titanicus'', Chaos Titans are depicted as constantly screaming their names in corrupted code language.
* MalevolentMutilation: Chaos cultists commonly mortify their flesh with carvings of symbols representing their patrons. Those practicing their faith in secret limit this to small carvings, easily covered up. Once they are operating in the open and know there is no more need to integrate themselves with Imperial society, many will start [[SigilSpam covering their entire body with such symbols]] as a symbol of how faithful they are.
** In ''Brothers of the Snake'', one such cult has a way to etch Chaos sigils on their bones without disturbing the flesh over them. An Inquisitor is very curious to know how they manage this.
* MyGodWhatHaveIDone: Sometimes, when they ''really'' want to have fun with their [[FallenHero once-heroic followers]], the Ruinous Powers will peel away the comfortable veil of madness from before their eyes and let them see the full horror of what they've become, then force them to admit that there's nothing else they ''can'' do to make it right. During the HorusHeresy, it happened to [[spoiler:Fulgrim, after killing Ferrus Manus]] and [[spoiler:Horus, after the Emperor mortally wounded him]].
* NegativeSpaceWedgie: Warp Rifts, tears in spacetime where the Warp and realspace gel together. The Maelstrom and Screaming Vortex are two well-known rifts, but the biggest and most infamous is the Eye of Terror. Formed by the birth of Slaanesh, it covers nearly all of the original Eldar empire and has irredeemably corrupted every planet it touches. It also serves as a home and headquarters for the Iron Warriors, Death Guard, Thousand Sons, and Word Bearers.
* PowerUpgradingDeformation: Most Chaos mutations gifted to its followers.
* RealityIsOutToLunch: In the Eye of Terror.
* RedRightHand: Marks of Chaos.
* SenseLossSadness:
** The only way to effectively torture Slaaneshi cultists is to stick them in a sensory deprivation tank. One crafty Inquisitor figured this one out.
** Any Chaos Marine entombed in a Chaos Dreadnaught will eventually go insane for the same reason (reflected in the rules, even). In more recent editions, the Chaos Dreadnaught has been replaced by the Hellbrute. Entombment in a Hellbrute is more tolerable to the Chaos Space Marine because they will eventually fuse with the machine, regaining sensory information.
* TimeDilation: Time moves differently in the Warp, both faster ''and'' slower than the rest of space. Justified because the Warp sneers at such things "causality" and "logic".
* TooDumbToLive: Many lesser followers of Chaos expect to be paid with the 'blessings' of the Chaos Gods. They usually are turned into barely-functional mutants that serve as meatshields for Daemons.
** A number of their actions that they do also require great sacrifice to the Gods... though they're things that could've been done without bloodshed, and in some cases, technology.
* WarriorHeaven: The Warp. To them, though, it ''is'' heavenly, in contrast with how hellish it is for others.
** It's also heaven for the [[BloodKnight Orks]], for how much combat they can find.
---> '''Great Boss Tuska''': Told yer I knew where da best fightin' woz.

[[/folder]]

!The various forces and factions of Chaos

!!Factions with their own pages

* [[Characters/Warhammer40000ChaosGods Chaos Gods and Daemons]]
* [[Characters.Warhammer40000ChaosMarines Chaos Space Marines]]

!!Others

[[folder:The Lost And The Damned]]

[[quoteright:348:http://static.tvtropes.org/pmwiki/pub/images/Traitor_Guardsmen_1116.jpg]]
[[caption-width-right:348: More where that came from. ]]

->''Fear not Chaos, for it is our salvation! Praise the sun that brings the dawn of our final doom, for is not destruction simply creation reversed in slow motion?''

The Imperium... [[WorldHalfEmpty is not a happy place]]. It has been at war for the last ten thousand years, it has grown accustomed to think in apocalyptic terms: what is the value of life when faced with threat to their immortal souls? "We are at war for our very survival," goes another Imperial slogan, "No sacrifice is too great, no treachery too small." There are threats everywhere: cults fester in the hives, claiming dozens of planetary rulers in their membership; mutants and rogue psykers run for their lives from fanatical witchhunters; and humans in general hope for a better future.

As such, Chaos has no shortage of wretches for use as cannon fodder. The ranks of Chaos are vast: traitor regiments of Imperial Guard, renegade Admirals of the the [[BattlefleetGothic Imperial Navy]], jaded nobility forming cults for thrills, abhuman and mutant underclasses living in the ghettos of Imperial cities, slave soldiers raised in hell worlds, hordes of reanimated zombies, fallen clerics of the Ecclesiarchy, entire Xeno races fallen to Chaos, vast mobs of peasants desperate for food, freedom fighters and revolutionaries who do not truly understand the price of their new, dark allies... they are all now the Lost and the Damned.

The Lost and the Damned is a curious army: despite being the most commonly encountered form of Chaos fought in the game's lore, players cannot actually field it in tournaments, nor do they have a fully-developed model range. It received an army list during the previous Eye of Terror campaign, but unfortunately this has not been updated for the most recent edition and it is classified as an unofficial army. The Lost and the Damned play similar to the Imperial Guard, and indeed feature traitorous guardsmen as troop choices, but lack the loyalists' volume of heavy weapons, armor, or even morale. To make up for this, mobs of low-cost mutants and other rabble can be used to soak up enemy fire or swamp troop formations, while other Chaos abominations can serve as assault troops. Overall, this makes them a gimped version of the Imperial Guard, but a characterful army nonetheless and a force of [[VillainousValor extreme (evil) underdogs.]]

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!!Notable Lost and the Damned tropes include:

* ArmyOfThievesAndWhores: And they take that as a compliment.
* BodyHorror: Horrible mutants are a common sight in the Lost and the Damned.
* BadassArmy: In the background, they can occasionally be the superior of the Imperial Guard in terms of discipline and power, under competent leadership and backed by the infinite power of Chaos...
** RedshirtArmy - ...but more often than not they're just used as CanonFodder by Chaos Space Marines (at least in most of the fiction).
* BloodKnight: Any Khorne worshipers in a Lost and the Damned army. In particular, he is a popular patron for military units which go rogue and fall to Chaos, or armies raised from Chaos worlds, of which a Lost and the Damned army is likely to be substantially in part.
* BrainwashedAndCrazy: Considering the penalties the Imperium holds for the heresy of consorting with the Ruinous Powers, let alone the danger of getting the Ruinous Powers' attention in the first place, and the well-publicized insanity and expendablity of the lower-down Chaos followers, it is understandable that some Chaos lords have difficulty recruiting willing followers. Hence, they resort to more forceful measures instead. Certain pieces of ritual sorcery and direct exposure to daemonic influence can have the habit of breaking the will of individuals, blasting their minds into awestruck simpletons highly suggestible to the whispers of the Warp. Cults will often try to arrange such sorcery to cause a substantial portion of the planet to rise up in Chaos' name even if they would not otherwise, and many Lost and the Damned armies are composed of such thralls.
** This is a plot point in the Literature/CiaphasCain novel ''The Last Stand''. The book's BigBad is an extremely powerful psyker who can overwrite your mind and turn you to Chaos just by looking at you. He even has a retinue of ''Sisters of Battle'' that he corrupted in this manner.
* CorruptChurch: One of their HQ choices is a heretic leader.
* {{Cult}}: Many Lost and the Damned are essentially Chaos cultists. In truth, the entire army list is an expansion of the Cultist choice available to Chaos Space Marines.
* DemotedToExtra: Lost and the Damned didn't get an army codex for Fifth edition - unless you buy the [[CrackIsCheaper Imperial Armour books]].
** Sixth Edition provided a Chaos cultist unit to represent them, but full-fledged cult armies are still Guard-based.
** While still without a dedicated Codex, Sixth Edition's allies rules allows units to be combined from the Imperial Guard, Chaos Space Marines, and Chaos Daemons army lists fairly easily. While an informal grouping, this does allow players to build Lost and the Damned armies in an ad-hoc fashion.
* EverythingsDeaderWithZombies: One of the troops choices is a 'plague zombie horde' fielded in units of up to 50 making it possible to field [[ZombieApocalypse up to 300]] in a normal army. Given the right support they prove suprisingly effective.
* EvilIsNotAToy: Something many of these people should have remembered.
* FeelNoPain: Khorne's followers are too furious to notice, Nurgle's followers are too rotten and corrupt to notice, while Slaanesh's followers notice and enjoy it thoroughly.
* GasMaskMooks: Especially the Dark Vengeance cultists.
* GenreBlind: Considering the (well publicized) fact that Chaos uses human sacrifice for anything more complicated than boiling water, it's a wonder anybody is dumb enough to join them...which in turn gives you some idea of [[WorldHalfEmpty just how awful]] life in the Imperium can get.
* JumpingOffTheSlipperySlope: Many of the Lost and the Damned were not always evil and had no idea what they were getting into until it was far too late.
* LargeAndInCharge: Another HQ leader choice is a Chaos Space Marine overseeing the rabble.
* MadScientist: The members of the Dark Mechanicus. Free of all the restrictions of the Adeptus Mechanicus, they innovate much more than their loyalist counterparts. However some of those restrictions include "Do not put Daemons in your tech" and "Do not make evil killer robots".
** Psycho-fanatic killer [[UnwillingRoboticisation cyberzombies]] made out of [[BodyHorror lobotomized criminals]] are [[NotSoDifferent perfectly okay for the Imperium to use]], though.
* PaletteSwap: It is entirely possible (and often necessary in lieu of their own codex) to field a Lost and the Damned army of traitor guardsmen, using Imperial Guard rules, units, and equipment, different only in their allegiance to the Ruinous Powers. This is pretty reasonable in the setting, and offers a player some interesting options for converting and painting "profane" versions of normal Imperial Guard.
** [[CrackIsCheaper If you have the money]], Forge World, a Games Workshop subsidiary, [[http://www.forgeworld.co.uk/Warhammer-40000/Chaos/CHAOS_RENEGADES offers a good number of Chaotic counterparts to Loyalist Imperial Guard units]], as part of a Vraksian Renegade Militia army list, but they can just as easily be used with the Imperial Guard codex.
* PsychoSerum: Many of the followers of Slannesh in this army will be hopped up on some cocktail of combat and recreational drugs.
* VillainousUnderdog: Seriously outgunned by both their allies and the Imperium, the Lost and the Damned have only their numbers and their madness to aid them.
* VillainousValor
* ZombieApocalypse: Nurglite Plague Zombies are a troops choice. With the right build, you can have an almost entirely zombie army with which to [[ZergRush swamp the opposition]].
[[/folder]]

[[folder:Other]]
* Any species with psychic abilities can be tainted by the Warp, including animals.
* ''TabletopGame/RogueTrader'' gives a rare example of an entire [[Characters/Warhammer40000Eldar Eldar Craftworld]] consumed by Chaos: Lu'Nasad. Three "Aspect Shells" were formed from ruined Aspect Shrines, spitting out undead Dire Avengers, Warp Spiders, and Wraithguard.
** Another Craftworld is Kher-Ys, whose Avatar was corrupted by Slaanesh.
[[/folder]]

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-->''Cast down the idols! Destroy the temples! Slay the priests! Show these fools that they worship nothing more than a rotting corpse!''

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