"Basically you're fucked like in Warhammer Fantasy Roleplay, only instead of dying from blood poisoning caused by a dirty pitchfork you get to have your innards blown across the wall and then subsequently set on fire by a plasma gun (probably your own)."
Dark Heresy is a Warhammer 40,000pen and paper roleplaying game published by Fantasy Flight Games using a mechanical system similar to Warhammer Fantasy Roleplay. It has the players assume the role of Acolytes of the Holy Inquisition in the grim, dark future of the 41st millennium, rooting out heresy among the Imperium wherever it may be arise. Notable for having over five consecutive pages entirely filled with Critical Hit Charts.Dark Heresy is also the basis for a series of novels written by Sandy Mitchell, of Ciaphas Cain (HERO OF THE IMPERIUM!) fame. The novels star the "signature characters" used by the rulebook for its gameplay examples: former arbitrator Mordechai Horst, tech-priest Hybris Vex, sanctioned psyker Elyra Yivor, Redemptionist assassin Keira Sythree, and guardsmen Danuld Drake and Vos Kyrlock. So far Scourge the Heretic and Innocence Proves Nothing have been released.A second edition of Dark Heresy is currently in development, and much as with its sister game Only War, Fantasy Flight Games has released a fully playable "beta" version for purchase. As an incentive to participate in the beta, anyone who purchases it will receive an equivalent discount off the full .pdf version whenever it becomes available.See also Warhammer Fantasy Roleplay (its fantasy counterpart); Rogue Trader, Deathwatch, Black Crusade, and Only War (its sister games); and of course Warhammer 40,000, as Dark Heresy (unsurprisingly) shares a great number of tropes with its parent game. Also check out Adeptus Evangelion, a fan-made conversion for running games set in the Neon Genesis Evangelion universe.
The game provides examples of:
Arc Words: Not for the game as a whole, but the phrase "come and see" is obviously intended to be used as Arc Words in any storyline involving the Menagerie.
Arm Cannon: The Integrated Weapons from The Lathe Worlds.
Anti-Villain: Ascension gives us Imperial Governor Malaki Vess of Zweihan’s World, one of the few hive worlds in the Imperium that isn't a Crapsack World. However, the Administratum is planning to levy heavier tithes that will change all that, and so Vess is planning to secede from the Imperium in a desperate attempt to keep his world from falling apart.
A-Team Firing: This is the case when any character who is not optimized for gun skills makes attacks with weapons firing on fully automatic. Surprisingly, this is actually one of the more effective combat strategies, as the application of More Dakka to intentionally suppress targets will give the opposing force penalties regardless of how much actual damage it does, allowing those characters in the party who are optimized for gun skills to take careful aim to finish off suppressed foes.
Awesome, but Impractical: Plasma guns shoot miniature suns as ammunition. Unfortunately, the ones in the corebook are also hideously expensive, slow to reload, prone to disastrous overheating, require time to recharge between each shot, and (as of Errata 2.0) only do about as much damage as a bolter. Luckily, the plasma weapons included in the Inquisitor's Handbook have a bit more bite to them, and Ascension introduces the rules for "military-grade" plasma weapons included in Rogue Trader.
If the GM is being stingy with the Thrones, even the iconic bolter can descend into Awesome, but Impractical territory, since each individual bolt round costs the same as three hundred and twenty bullets — leaving the poor Guardsman to decide whether he wants to shoot the giant gribbly monster with his bolter, or eat for the next two weeks. And that's before you get to the fully-automatic heavy bolter. It costs four hundred and eighty Thronesto fire this gun for fifteen seconds. When the rulebook says that "a man might beggar himself to own one," it is not kidding.
Brown Note: Komus, the Tyrant Star, whose appearance in a system has been known to drive entire planets insane.
Tech Priests can learn Feedback Loop which is like a microphone-on-speaker hiss, excpet it paralyzes nervous systems.
Bullet Proof Vest: Although Imperial Guard issue flak armor is derided in the wider fandom as having the protective qualities of a t-shirt against military-grade weaponry, it is actually some of the better armor that an acolyte can start with. Further, it is common and inexpensive enough that a group pooling its resources should be able to afford to equip every member with at least this, it is light enough that even physically frail characters can comfortably wear it, and it provides fair protection across the entire body. Considering how deadly combat is in this game, almost everyone needs some fair protection. This tends to put it into Boring, but Practical territory.
Not to mention that full military-grade flak is so commonplace, and imperial culture so militaristic, that the Acolytes can not only wear it in most situations without looking out of place, but they could even wear it as a disguise sometimes.
By-the-Book Cop: Any Arbiter class character who is played straight will necessarily be one. However, Imperial law tends to be pretty permissive about brutal enforcement as it is, "always err on the side of harshness" being a sanctioned policy. That said, Arbiters might take issue with some more Radical Inqusition operatives if those Radical options take them on the bad side of Imperial law.
Church Militant: In addition to the standard Cleric career path, the Inquisitor's Handbook offers Sisters of Battle as a character class option. The Blood of Martyrs sourcebook offers expanded options for both.
Church of Happyology: One adventure includes a particular Cult of the Emperor called "The Joyous Choir" with a central dogma that the God Emperor wants his subjects to be happy, and they can be happy by finding their true place in His plan. People are judged on how close they are to their place in the Emperor's will by use of an electronic scanning device, and based on the results of that scan they receive coaching from the cult's priests. Many young planetary nobles have joined, and have indeed enjoyed greater prosperity for themselves since joining. Of course, a rational-minded Inquisitor will point out that by forming various cooperative and trade agreements between nobles who are members, of course they will find their fortunes benefit. Said cult also has some records it would very much like to keep from public exposure...
Comically Inept Healing: Your own character can be this, if you attempt a Medicae check and roll poorly. You'll suffer an additional penalty for working on Xenos, unless they are Orks. With Orks you get a bonus, because they are so tough you can't possibly make the injury worse.... Orks, expecting a mad-doc, will only seek medical treatment when they have no other choice.
Conditioned to Accept Horror: The "Jaded" trait. Through either a lifetime of bad experiences, careful training, or just a callous nature, characters with this trait never have to take insanity checks from "mundane" sources of horror. Supernatural sources can still dredge up their fears though.
Continuity Nod: Two of the characters pictured in Ascension are easily recognizable to veteran Specialist Game fans as Inquisitor Covenant and 'Slick' Devlan, characters introduced in Dark Heresy's spiritual forefather Inquisitor. Ascension also finally attributes the "only the insane have strength enough to prosper" quote from the start of the Inquisitor rulebook to a specific individual: the rogue Inquisitor Felroth Gelt.
Critical Hit: Eight pages of blood-spurting, limb-severing, organ-cooking, bone-exploding charts, though generally these only apply once a character drops below zero Hit PointsWounds. Also includes the more traditional "extra damage on a good die roll" version as Righteous Fury: rolling a natural 10 on a damage die gives a player the chance to continue rolling damage dice until they stop rolling a 10.
Chunky Salsa Rule: Taking more than eight cumulative points of Critical Damage will kill you in some horrendously gruesome and awe-inspiring way. Such as, oh say, "Both head and body are blown into a mangled mess, instantly killing the target. In addition, if the target is carrying any ammunition it explodes dealing 1d10+ 5 Energy Damage to anything within 1d5 meters." And that's just at 7.
"It has the best critical hit charts ever made. You don't even need the rest of the game (although it is all good, it's just a LOT). Just start a campaign, wing it, and whenever anyone gets a good hit, roll on the critical hit charts. Holy fucking hell, did boiling bone marrow just turn my femur into a frag grenade? Fuck."
Crapsack World: In addition to the general crapsackiness of the 40k universe as a whole, you have the feudal hell that is Sepheris Secundus, the "Scrivener's System" of Prol (where a civil war is brewing because they're running out of places to store all the paperwork), and Klybo, where various settlement attempts have been so spectacularly unsuccessful that the planet's name has become the Calixian equivalent of "SNAFU."
Read the Prol example again. Every word is LITERAL.
Cult: Everybody, including the player characters. "The only cult that we do not abhor is that of the Emperor!"
Deadly Decadent Court: Par for the course among the Imperial nobility on more established worlds, but this is the particular hat of the hive world Malfi, who take it Up to Eleven. They are not necessarily all evil, but it is an environment in which one must lie, mislead, backstab, and maintain the courtly masquerade, or suffer long torments as those who do rip their rivals' houses apart over the course of years.
As well as Woe, which is listed in the core rule book as "A death world. Extremely hazardous." Sounds nice, doesn't it?.
Woe is later explained to have nothing but plant life on it. All of which are omnivorous, and can also move about, albeit rather slowly. These ultra deadly trees have been noted to not only shift around overnight like The Brothers Grimm trees, but are also smart enough to team up on larger trees. As far as the foliage is concerned, you are food.
Dodge the Bullet: Every character gets one "Reaction" move during their enemy's turn. Among other things, this can be used to parry an opponent's attack, or in gun fights used to dodge an enemy's shot. Of course, characters do only get one Reaction per round, which means it can be overcome by More Dakka on their enemy's part, unless that combat dodge is used to Take Cover, which is the practical option when being shot at.
Dying Planet: The world of Sinophia at the edge of the Calixis Sector was the staging point for the Angevin Crusade that brought the sector into the Imperium millenia ago. At that time, Sinophia's infrastructure and economy were greatly expanded to support the crusade, and the world benefitted as immigrants arrived, industry flourished, and the planet became wealthy and influencial. However, as the crusade wound down and the conquered worlds settled fully into the Imperium, the importance and influence of Siophia declined. These days, the world is slowly decaying, in a perpetual economic downturn, with a shrinking population, an unmaintained infrastructure, and various noble houses bickering among one another with none able to wield the influence to steer the planet to recovery.
Hand Cannon: One of the handguns described in the game is literally referred to as a Hand Cannon. It's a solid-projectile firearm with recoil so powerful it requires a two-handed grip (or special gloves) to be used effectively. It is also the smallest pistol in the game that qualifies for this trope.
Hazmat Suit: The Vile Savants, daemons of Nurgle responsible for one of his Zombie Apocalypse plagues, take the form of a walking hazmat suit filled to the brim with pestilent filth and diseased maggots. You can also buy a regular Hazmat suit used by sewer workers that gives you resistance against fire and acid, but it's not meant for combat so it has heavy penalties to Agility.
Heroic Sacrifice: Encouraged in the Game Mastering section of the rulebook. The system is already pretty deadly, Player Characters have uncertain life-expectancy, and the GM is discouraged from softpeddling that, in order to underscore the brutality of the setting. However, the GM is encouraged to bend the rules a little when a character is facing certain death in order to make that death spectacular, with the explaination that a player should not be afraid of their character's death, but they should not feel like their character can expect to "die like a chump".
Heroic Willpower: The Inquisitor class gets the special ability "Indomitable Will of the Inquisition"; which allows them to pass a willpower test perfectly once per session.
He Who Must Not Be Seen: The Unknown Heretic is an in-universe example of this — the only person in existence to be branded Excommunicate Traitoris by the Inquisition without anyone being certain he actually exists.
Horde of Alien Locusts: The Creatures Anathema supplement gives us the Xothic Blood Locust, a literal case of this trope. Intersteller travelers may unknowingly carry their eggs on their clothes or in cargoes they pick up, which can lead to disastrous swarms when they hatch on some other world. Their name comes from their preference for draining blood from living creatures, which a swarm of them can do completely in a matter of seconds, though they will consume almost any organic fluid they can find. The same supplement also gives profiles for Genestealers and Lictors, which are the harbingers of alien locusts orders ofmagnitude worse...
Immortality Immorality: Dark Pacts of Longevity, which involve selling your soul to a daemon, and the Halo Devices, which turn you into an inhumanly cruel, cannibalistic, immortal, insane, super strong, nigh invulnerable, lightning fast abomination against all sanity.
And an even worse group of Knights Templar are the main villains of the Apostasy Gambit trilogy, Maledictor's Hand— i.e., the people who believe the Calixis sector is utterly corrupt and should be cleansed... and use the power of Tzeentchhimself to bring this about. At least the Inquisitors have a relatively high smart-to-dumbass ratio. The Maledictor's Hand doesn't even have that excuse.
Furthermore all ranged attacks get a +30% to hit at point blank range.
Off with His Head!: Happens when one scores high on a head critical hit chart. Scoring even higher leads to such pleasant outcomes as nearby combatants being showered with skull fragments and brain matter, the local area becoming difficult to walk through for all the gore on the ground, and the victim being killed so gruesomely that his friends must fight the urge to flee from his killer for a couple of Rounds.
One Stat to Rule Them All: Fate Points. you can start with 1 to 4 of them. Each fate point can be used to make a reroll once per session, and they can be permanently used up to avoid dying.
The Paladin: The Adepta Sororitas career introduced with The Inqusitor's Handbook. Each is an Action Girl, to varying degrees, and they can use Fate Points in unique ways to manifest "acts of faith." However, they lose these abilities if they gain more than a small amount of corruption points, and the very fact of who they are limits and dictates how they behave and what they do. For this reason, the book recommends limiting this class to experienced roleplayers.
Power Perversion Potential: Biomancers can do some... interesting things with their abilities. They also have a tendency to be huge party animals, as they can engage in gluttony and debauchery and still remain fit and healthy through use of their powers.
Properly Paranoid: Stands out as a games system where having Paranoia is not a character flaw, but a purchasable Talent that grants bonuses (namely, +2 to initiative and the ability to make awareness checks in situations normal people couldn't). A number of role-playing suggestions are given for people who take the Talent but nothing that mechanically impairs you in any way.
Religion is Magic: The Blood of Martyrs supplement includes a lot of options of this nature.
Short-Range Long-Range Weapon: Very much averted, especially when compared to equivalent weapons from the tabletop game. However, thanks to their special rules, shotguns are still most effective at point-blank range. Notably, weapons generally have no Arbitrary Maximum Range, just a range beyond which scoring a hit is extremely improbable.
Adept Grendel, a character from a /tg/ copypasta famous for one-shotting a Charnel Demon was featured on the Radical's Handbook preview.
The Skin Taker of Fedrid is an invisible monster that kills for no apparent reason and takes grisly trophies from its prey. Sound familiar? (Curiously, while "technologically-advanced alien big game hunter" is implied as a possible identity for the Skin Taker in its description, neither of the two writeups provided for it take this form.)
Splash Damage Abuse: An advantage of grenades is that they do not need to land at a target's feet to do their damage, they just need to land in the target's general area. This makes them ideal for cell members who lack combat specialization to still contribute in a fight. Hucking a grenade into the cover enemies are using will either signifigantly damage those enemies, or flush them into the open for the thrower's more combat-skilled teammates to finish off.
Splat: The different character classes/career paths (Adepts, Arbiters, Assassins, Clerics, Guardsmen, Sanctioned Psykers, Scum, and Tech-Priests), as well as splats for world of origin (Feral, Imperial, Hive, or Void-Born). The Inquisitor's Handbook adds the Adepta Sororitas career path, rules for alternate homeworld types and specific homeworlds, and sub-splats (Background Packages, Alternate Career Ranks, and Elite Advances) dedicated to covering world-specific variants of the greater career paths and life-changing events in an acolyte's career. Ascension adds "ascended" versions of all the base classes (Sages, Judges, Death Cult / Vindicare Assassins, Hierophants, Storm Troopers, Primaris Psykers, Desperados, and Magi respectively, though there is some overlap), as well as the Crusader, Interrogator and Inquisitor ascended careers. And then there's The Radical's Handbook, which adds evil versions of a lot of these splats. Is your snowflake special enough yet?
Super Soldier: If the Vindicare Assassin wasn't enough, the Daemon Hunter supplement includes rules for Grey Knights, the most superior of the Imperium's Super Soldiers. Deathwatch also includes suggestions for how to integrate Deathwatch Marines into games of Dark Heresy.
Take Cover: Given how deadly combat in this game is, and how effective cover is at preventing a character from getting hit, this is practically a necessity against opponents with guns. Even well-armored characters will usually want to get into cover to prevent a Death of a Thousand Cuts from the little Scratch Damage that manages to get through their protection.
Trap Master: Acuitor Mech-Assassins are Techpriests who have been initiated into a secret society that destroys threats to the Priesthood of Mars. Fiddling with tech so that they become deadly to said enemies is the preferred method, and their universal Trait makes them very good at it.
Took a Level in Badass: The Ascension supplement, which allows players to become Inquisitors and Throne Agents a la Eisenhorn or Ravenor, is this for the entire line as a whole. Any character carried over from the stock leveling system will literally be taking a level in some variety of badass when they make the transition.
Un-Cancelled: The unusual circumstances behind the game's cancellation and uncancellation, both within a month of its initial release, are explained more fully on that page.
Urban Segregation: Sepheris Secundus is a particularly extreme example of this, even by typical Warhammer 40,000 standards.
Well-Intentioned Extremist: Over the course of a campaign, you will bribe, torture, and murder. You may even set entire planets to the flame. You'll do it because everything you're up against is so much worse.