Dark Heresy

Dark Heresy

RPG published by Fantasy Flight Games
Rule System	d%
No. of Players	3+
Session Time	10+ minutes
Authors	Owen Barnes, Kate Flack, Mike Mason
First Publication	2008
Essential Books	Dark Heresy Core Rulebook The Game Master's Kit Purge the Unclean The Inquisitor's Handbook Disciples of the Dark Gods Creatures Anathema Tattered Fates Damned Cities The Radical's Handbook Ascension Dead Stars Blood of Martyrs The Black Sepulchre Daemon Hunter Church of the Damned Book of Judgement The Haarlock's Legacy Trilogy The Chaos Commandment The Lathe Worlds

Dark Heresy is an RPG set in the Warhammer 40,000 universe. It is to 40k as Warhammer Fantasy Roleplay is to Warhammer Fantasy Battle, and indeed uses a very similar system.

Basically you're fucked like in WFRP, 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). This is if you are lucky. All kinds of worse things can happen - being eaten by xenos or hungry daemons, afflicted by Chaos mutation, and if you are especially unfortunate... *gulp* ...surviving to reach Inquisitorhood. 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.

All player characters are supposed to be human acolytes working for the Inquisition, although they may come from many different vocations. From the feral world warrior to the hive ganger, from the inducted Guardsman to the detached Sister of Battle. However, whilst the official adventures focus on inquisitorial investigations, the authors themselves have acknowledged the ease of relocating the game's focus to other aspects of the 41st millennium, such as an Imperial Guard platoon where all player characters are soldiers in one of the many warzones.

Some anons have expressed dislike towards Dark Heresy due to the limited power-level, as the current official ruleset does not allow players to assume the roles of Spess Mehreens (with the exception of the Grey Knights, but the splatbook that introduces them warns you that letting the token Ward fanboy play one may lead to overpowered game-wrecking bullshit if not done very carefully) or any aliens, since those characters would simply be unfit for this kind of gameplay. So, if you want to play Spess Mehreens, Farseers or Fire Warriors, Dark Heresy might not be for you - get the Inquisitor, Rogue Trader, Deathwatch, or Black Crusade additions to fulfill your Mary/Marty Sue/Stu fantasies.

However, there are also several player-created supplements dealing with additional career paths like Adeptus Astartes or xenos races like Orks. Check the Dark Reign link at the end of the page for this kind of material, should playing ordinary people with balls of steel be beneath your dignity.

Careers

Including the Inquisitor's Handbook, Blood of Martyrs, & Daemon Hunter supplements, the playable character classes and career trees are:

Adept (Lexograph or Logister) - The brains of the party, quite useful when it comes to knowledge.
Adepta Sororitas (Famulous, Hospitaller, or Battle Sister) - Nuns with guns. The Inquisitor's Handbook adds in Sisters of Battle, but it represents them in a general light, so one might just be a booky nun rather than shooty. With Blood of Martyrs, rules are added in for strictly being bolter-bitches and nothing else.
Arbitrator (Enforcer or Investigator) - Judge Dredd in space. 'Nuff said.
Assassin (Nihilator or Infiltrator) - Murderhobos with little to no training or scrubs who really wish they were working for the Officio Assassinorum. (depending on career).
Cleric (Confessor or Zealot) - Clerics of the Empra who kick arse for the Throne. Imagine a priest with a sawn-off shotgun.
Guardsman (Stormtrooper, Officer or Sniper) - See Imperial Guard
Imperial Psyker (Savant or Scholar) - Can try to channel the chaotic energies of the warp, usually with mixed results.
Scum (Ganger or Fixer) - The rogues of 40k actually have a skill called "blather". Apart from that, the name says everything else you need to know about them.
Tech-Priest (Technomancer or Omniprophet) - Borg clerics of the Omnissiah.
Grey Knight (Strike Squad, Purgation Squad, or Purifier) - Super powerful, super fanatical Space Marines owned by the Inquisition for only the most dangerous and imperative missions, like killing Greater Daemons or Chaos Primarchs. If you choose this, you will single handedly turn your whole campaign into a Mary Sue campaign centered around you being a dickass.

Additional Career Paths are available in the splatbooks, such as all of the Ascension career paths.

Crusader A Paladin pinched from 3.5 and made grimdark.
Death Cult Assasin The real deal. What Murderhobos from the core rulebook wish they were.
Desperado Scum who have managed to actually become GOOD at what they do, becoming Made Men and/or Mafia Dons.
Hierophant If a Cleric is a Priest, these guys are Bishops.
Interrogator Inquisitors in training.
Judge Do we really have to explain this?
Magos As to Techpriest as Hierophant is to Cleric.
Primaris Psyker Rape on legs; a Primaris geared towards battle can roll 14 power die, and can kill twenty people at once with a single cast.
Sage Even Adepts think they're nerds.
Storm Trooper Guardsman Special Forces. See Imperial Guard.
Vindicare Assasin Can be anything from a Murderhobo who's good with a gun, or a gaurdsman sniper.
Inquisitor Nobody expects them. except when they do.

Although all characters need to be human, their origins may vary wildly. To give just a few examples: feral world people tend to behave like Conan or Tarzan whilst hive-worlders could best be compared to Adam Jensen or Shadowrun characters, and the Schola Progenium produces fanatical Nazi zealots who are blissfully ignorant of the Imperium's more corrupt elements. Voidborn characters are usually just strange because of their pale skin - good luck convincing that angry mob over there your friend isn't a mutant.

Important Things to Remember

Grim darkness is grim.
Nobody expects the Imperial Inquisition.
- Not even the Inquisitor.
When the Psyker attempts to use his powers, watch for strange things happening. Preferably twenty metres away.
That guy over there looks strange. He is probably a heretic.
USE COVER!
USE GRENADES TOO!
If you meet a Chaos Space Marine; you're already dead, you're just too stupid to realize it yet.
Everything is baleful. Everything.
Sooner or later your GM will discover the Slaugth. If you suspect that this may be the case (maniacal laughter is a tell-tale sign), buy flame weapons. All the flame weapons.
You have a solid projectile or bolt type gun, get a fire selector. They're relatively cheap, and effectively triple your magazine size by allowing you to have three magazines loaded at the same time.

How To Survive A Firefight

Dark Heresy has something of a reputation for being highly lethal - your average starting character has somewhere between 9 and 14 wounds at most, and most rifle-class weapons do 1d10+3 damage on a hit - but assuming your GM isn't a complete dick and your characters fight intelligently, you can generally come off very well against most varieties of human opponent, and careful planning and equipment selection can even the odds even when fighting against xenos or demons.

Crucially, nobody takes as much damage as you might assume at first glance. Although the listed damage of weapons seems high compared to a character's total wounds, your toughness bonus and armour points both considerably reduce incoming damage. A starting Guardsman ignores between 6-8 points of damage from every attack, and that's assuming he's standing in the open like a gormless idiot. On top of this, one of the most commonly forgotten aspects of the Dark Heresy combat system is that everyone gets one Reaction per round, which can (among other things) be spent at any time to attempt to dodge or parry an attack, completely negating it. Although the odds of success aren't always fantastic, it's better to try and dodge that shot or parry that axe than sit there and take it!

Equipment selection is also very important. Although badass characters can indeed be very dangerous even with poor gear, even a low-rank inexperienced character can dramatically improve their combat effectiveness by making prudent choices when it comes to their loadout. If an acolyte cell plans together and chooses their equipment to complement each other, they can make themselves very deadly as a team. For a start, a set of Guard Flak armour is inexpensive, commonly available, comfortably wearable by all but the most unusually weedy characters, and dramatically improves your resilience to incoming fire. Any cell of acolytes that expects serious combat should be able to at least equip all its members with a set of Guard Flak, if it can't afford anything better.

When it comes to weapons, anyone can and should carry a few grenades if at all possible. Even for a character with low ballistic skill and no proficiency with grenades, all you need to do is land them reasonably close to whoever you're trying to hit. Depending on the precise situation, you might even be able to get away with dropping them on unsuspecting opponents from above or letting them roll down slopes to your foes, and they have the potential to injure multiple enemies at a time. Used properly, then can help turn the tide in a battle where you find yourself outnumbered.

The cell's primary firearms should be chosen to work well together. Weapons that can fire fully-automatic and weapons that have the Accurate quality are generally your best choices. A good hit with a full-auto burst can do serious damage to enemies, but by far their most important aspect is the ability to lay down Suppressive Fire. Crucially, even if you have terrible ballistic skill and no training with the weapon you're using, your ability to suppress enemies is completely unhindered. Your burst of fire almost certainly won't hit anything, but the difficulty of the test your foes must make to resist being pinned is unchanged regardless of how well you can aim. This can give less combat-oriented careers, such as the Adept, an important role to play when it comes to a fight, where they might otherwise have been reduced to hiding behind something heavy and occasionally plinking away with some crappy pistol.

High BS characters can be quite dangerous with fully automatic weapons, but should give serious consideration to using Accurate single-shot weapons, especially if they've picked up the Talents for making Called Shots at reduced penalty. Not only does an Accurate weapon grant an additional bonus to your chances to hit if you take the time to aim it, it can do extra dice of damage on a good shot - unlike a full-auto attack, this is a single hit that does more damage rather than multiple hits that are each individually subject to reduction by the target's toughness and armour. This makes Accurate weapons great at punching through the damage reduction of particularly tough enemies, particularly if combined with the Called Shot to aim for a part of the target that is less well armoured or isn't in cover properly. With appropriate weapon modifications (such as the Red Dot Sight) and a Half Action to aim, the acolyte is looking at at least a +30 bonus to hit. Most firefights will take place well within an Accurate weapon's effective short range, raising that bonus to +40.

Combine these two classes of weapon within your group, and you'll have some acolytes that lay down suppressive fire and force enemies into cover and some who can take accurate potshots at the suppressed enemies to take them down with little fear of receiving effective return fire. Any foe who manages to find cover sufficient to shield him from all shots can probably be reached with a well-placed grenade.

A good rule of thumb for any firefight is that if you're not in cover, all you should be doing is trying to change this state of affairs. Even if you're a tough guy in decent armour, the small amounts of damage that come through will add up if you're under fire by a lot of enemies. Take cover as quickly as you can whenever you can, and you drastically increase your odds of survival. Just as importantly, you must not be afraid of running away! The feeling that the group has to defeat every encounter that comes their way leads to many deaths. Sometimes, retreating in order to fight again some other day, hopefully better prepared, is the best option. If the fight isn't going your way - you're getting surrounded, taking too many injuries, or running out of munitions - make a break for it.

A cell of acolytes is at its most dangerous if it can prepare the area of the fight beforehand. Your role doesn't always have to be offensive, kicking in the cultists' door and firing wildly, hoping for the best; if you can figure out some way to lure your enemies to a carefully prepared killing zone (for example, your cell might pose as black market merchants with whom your enemies try to trade for supplies in order to bring them out of hiding), you hold a significant advantage. Heavy cover can be prepared in advance, with machine-gunners ready in hiding to cut down unsuspecting foes; scenery where enemies are likely to try and take cover once the fight begins can be rigged with booby traps or remote-detonator explosives. You can also position your group to surround the enemy and possibly attack from above, making it very difficult for them to find effective cover in the first place.

For psykers, you have ridiculously high chances of your brain exploding. Only cast if you need to, and do it at Fettered as much as possible to minimize perils. If you do cast, think carefully what sort of mind bullets you'll throw.

In conclusion, equipment and cohesive tactics are what make or break an acolyte cell in a serious firefight. Although having experience, high skills and plenty of talents helps, a lack of these is more than made up for by pimped out gear and a good plan. If you have both, your cell can become a force to fear even for very well trained and equipped enemies.

Sample Combat

The party of bold/stupid/adventurous and ignorant members (perfect =][= material really) was investigating a psychic disturbance up on a large hillock of shale and scree. Upon getting most of the way up, the Arbites slips arse over head on loose scree and goes tumbling down, taking the Scum with him in the process in a manner which would please the chaos gods with its twisted irony... despite the Arbites denying it was deliberate as they tumble down together.

Both him and the Scum are really busted up in a tangled mess of broken bones, skulls and dirt at the bottom of the hill. The well-intentioned but stupid Psyker decides to save the day by announcing that he'll fix them up, and before Angry Nun can finish screaming out "no don't the veil is weak here!" he's happily botching a power roll.

"A Horror of the ruinous ones appears!"
Arbites promptly passes out in fear
Scum runs screaming, defecating and hobbling
Tech Priest runs behind the truck, soiling his robes
Psyker runs screaming so he can die tired
Angry Nun gets angry(er)

DING DING
Round One!
Horror sets Psyker on fire and sets off in pursuit
Angry Nun hauls out 10G sawn-off and holy plasms of banishing, begins chasing the Horror (bold and stupid!)
Psyker burns a bit but is still mostly functional at running
Tech Priest snaps a shot off at the horror with las-carbine, doesn't do very much, resumes hiding
Scum: "Weeeeza gunna diiiiiie!"; runs screaming for cover
Arbites: "zzzz"

DING DING
Round Two!
Horror lands a good old fire-bolt to the back of the Psyker and sets the truck on fire
Angry Nun scores a good hit with some banishing water and hurts the Horror a bit
Psyker is in a fair bit of pain, still on fire and running around going "Ow! Ow! Ow! Oh God-Emprah it burns!"
Tech Priest notices the sacred machine is in pain and needs fixing
Scum does what scum do and hides under the truck
Arbites: "zzzz"

DING DING
Round Three!
Horror bolts the Psyker a bit more
Angry Nun grievously hurts the Horror a bit more
Psyker is still on fire and roughly at about 0 wounds and about to go into criticals, agony level of about 8/10
Tech Priest is doing badly at putting fire out
Scum catches fire underneath the truck
Arbites: 'zzzz'

DING DING
Round Four!
Horror blows the foot off the Psyker with a bolt
Angry Nun is busting up the Horror pretty good, but a bad roll on the dice means a lot less damage than hoped (even after a re-roll on a fate point)
Psyker, still on fire, minus foot and now crawling in agony
Tech Priest manages to get the truck fire under control
Scum rolls around on fire
Arbites wakes up, shrieks a bit and passes out again

DING DING
Round Five!
Horror lands another bolt...
Angry Nun snaps off some serious pain on the Horror, he's looking very wobbly now
Psyker detonates in a shower of meat, shrapnel, armour and exploding munitions; the area is now safe, except for the Horror
Tech Priest gets injured by chunks of Psyker
Scum gets injured by chunks of Psyker, continues burning
Arbites: 'zzzz'

DING DING
Round Six!
Angry Nun vs Horror at the same initiative
Angry Nun pulls trigger on sawn-off shotgun
Horror lets loose with a Psychic Scream
Angry Nun falls down on 5pts of Fatigue, Horror explodes in shower of gibs and returns whence it came
Psyker rains down on the landscape in burning chunks
Tech Priest puts the Scum out
Scum is much happier now that he's not on fire anymore
Arbites: 'zzzz'

Dramatis Personae of the Calixis Sector

Historical

Solomon Haarlock: Rogue Trader, discoverer of the Calyx Expanse.
Golgenna Angevin: Lord Militant of the Angevin Crusade, which won the Calixis Sector for the Imperium. The crusade was a success in spite of his gross incompetence, mostly due to the actions of Drusus (see below).
Drusus: General in the Angevin Crusade, responsible for cleaning up Lord Militant Angevin's massive cock-ups. Was assassinated on Maccabeus Quintus and was resurrected by the Emperor (at least supposedly), and was declared a Living Saint. After the crusade, became Calixis' first Lord Sector Governor.
Erasmus Haarlock: The last known member of the Haarlock Dynasty, who killed the rest of the family to avenge the death of his wife, and attempted to harness the power of the Tyrant Star to resurrect her. Hinted at being one of the Seven Devils of Calyx and the herald of the End Times. Continues to not be a ripoff of Captain Harlock.
Umbra Malygris: An Arch-Magos and perpetrator of one of the most wide-scale tech-heresies in the sector's history, whose influence is still feared to this day.
Cassilda Cognos: Founder of the Tyrantine Cabal.

The Holy Ordos

Aegult Caiden: Head of the Calixian Conclave. Spends most of his time being mysterious and shit. Nobody even knows what he looks like, because he always wears a mask.
The Tyrantine Cabal: A group of Inquisitors dedicated to studying the Tyrant Star. Responsible for a lot of coverups even from the Inquisition as a whole. Members include:
- Anton Zerbe: Head of the Tyrantine Cabal, like any good Amalathian, he's trying to keep the other Cabal members from going at each others' throats.
- Rykehuss: Monodominant Witchhunter with all the subtlety of a brick to the face. Has a penchant for burning entire towns to the ground just because he has a funny feeling.
- Ahmazzi: Three hundred-year-old Daemonhunter. Wants you damn kids to get off his lawn. Is actually a wanted heretic with an Excommunication Order.
- Astrid Skane: A Recongregator, otherwise a female version of Judge Dredd. Can be quite subtle despite what you think, and hates Nobility.
- Van Vuygens: The foremost expert on Tyranids in the Calixis Sector. Currently investigating a large-scale xenos incursion that may or may not be the Slaugth.
- Globus Vaarak: A fat, sarcastic Amalathian who resembles Sloth from The Goonies if he had three artificial limbs. Responsible for training an above-average number of promising Interrogators.
- Olithane Rathbone: As an Istvaanian, she's the Cabal's resident shit-stirrer.
- Soldevan: Xanthite who's quite a few cards short of an Emperor's Tarot. His brain is in a jar he carries around. Did we mention he's crazy?
- Vownus Kaede: A psyker and Polypsykana sympathizer. Enjoys trolling Inquisitor Rykehuss.
- Al-Subaai: The newest member of the Cabal and former Interrogator for Inquisitor Van Vuygens. Focuses mainly on the Cold Trade. Knows the true purpose of Aglets and boybands.
The Scholariate at Arms: A highly effective Ordo Malleus Chamber dedicated to the principle of strength through competition, and tolerates a broad number of factions within its membership. Members include:
- Ghankus Dhar: Proctor of the Scholariate. Lone survivor of a major Chaos incursion on Spectoris.
- Suresya: A secretive but effective Daemonhunter. Secretly a Phaenonite.
- Octus Enoch: Specializes in preventing Daemonic incursions through prevention or fulfillment of prophecy; may be an Ocularian for this reason.
Silas Marr: An extremely controversial Inquisitor obsessed with the Haarlock Dynasty.
Glavious Wroth: An Amalathian dedicated to policing the Inquistion itself, which has naturally made a lot of enemies (particularly the Tyrantine Cabal).
Antonia Mesmeron: An Oblationist whose presence, identity and purpose is unknown to the Calixian Conclave.

Adeptus Terra

Marius Hax: Current Lord Sector. A complete hardass who rules the Calixis Sector with an iron fist. Known to be paranoid about that control slipping away from him. Presently being manipulated by the Istvaanian faction and undermined by the Recongregator faction.
Duke Severus XIII: Lord Sub-sector of the Periphery and descendant of a Rogue Trader screwed by Drusus after the Angevin Crusade. Declared independence from the Imperium with the help of a kabal of Dark Eldar. Not mentioned in Dark Heresy, but the default setting for Only War deals with Severus getting his shit kicked in by the Imperium, Warboss Ghenghiz Grimtoof Git-Slaver, Sektoth the False Whisperer, and his Dark Eldar "allies".

Ministorum

Ignato: Arch-Cardinal of the Calixis Sector, Cardinal of the Golgenna Reach, and head of the Tarsine Synod. Spends most of his time struggling to unify the sector Munitorum, dealing with Hestor's schemes and attempting to root out the Temple Tendency in the sector. Secretly part of a conspiracy to destabilize the sector, even though this completely contradicts the rest of his fluff and Hestor should have been given this role.
Kregory Hestor: Cardinal of the Drusus Marches and head of the Drusian Cult. Currently using the Maccabeus Schism to weasel as much power from Ignato as possible and increase the independence of his arch-diocese.
Pyris Valcarna: Cardinal of the Adrantis sub-sector. A major ally of Ignato. Focuses his time on the situation in Tranch and Magos Redole's research.
Quiro Olranna: Cardinal of the Josian Reach. A major ally of Hestor in his schemes.
Cal Sutai Arran: Cardinal of the Malfian sub-sector and head of the Periphery Church. Known as "the Venerable Cal," is the oldest and most respected member of the Calixian Synod. Worried that the Maccabeus Schism is turning into outright heresy. Rides around in a hoverchair armed with a fucking psycannon.
Fortis: Cardinal of the Periphery and the Halo Stars. A major ally of the Venerable Cal. In conflict with Hestor over the control of Port Wander and the Koronus Expanse beyond. One of the few individuals privy to the Margin Crusade's catastrophic failure (read: the fact that the Margin Crusade exists only in propaganda).
Dantius Landsholt: Cardinal of the Hazeroth sub-sector. Grossly incompetent but a loyal supporter of Ignato.
Yvenna: Cardinal of the Markayn Marches. In conflict with the Red Redemption. Holds a deep personal hatred for Cardinal Olranna.
Priam: Archdeacon Procurator of the Golgenna Reach. Secretly the High Priest of the Temple Tendency in the Calixis Sector.
Archdeacon Ludmilla: Leader of the Red Redemption in the Calixis Sector.

Mechanicus

Castellar: High Fabricator of the Lathes. Named after a font.
Ralwure the Golden: Second-in command of the Lathes. Head of a fundamentalist faction of the Calixian Mechanicus.
Halix Redole: The sector's foremost Genetor, responsible for several innovative organic devices and substances. Currently studying the Adrantis Civilization, a pre-Imperial human culture native to the sector.

Rogues and Heretics

Rogue Inquisitors

Felroth Gelt: A Xanthite Inquisitor on the run from the Calixian Conclave. Keeper of a voluminous journal that serves as a vehicle for much of Dark Heresy's fluff. Originator of that famous "only the insane have strength enough to prosper" quote.
Staven Arcturos: A Radical Inquisitor of the Xenos Hybris faction obsessed with the Eldar.
Natius Osrinn: A former protege of Inquisitor van Nuygens who became a Xanthite and headed out into the Koronus Expanse.

Other Rogue Servants of the Holy Ordos

Ferran Ghast: A former Interrogator of Inquisitor Cognos who sows apparently random mayhem throughout the sector.
Hettesh Kane: A sanctioned psyker formally working under the Ordo Hereticus, now a friend of the Burning Princess.
Seraph: A mind-cleansed former member of the Moritat death-cult in the employ of Inquisitor Mesmeron. Was once daemon-possessed, and may be succumbing to Khornate influences.
Cyrrik Scayl: A techpriest seconded to the Ordo Hereticus who became a disciple of heretek Nomen Ryne. Currently attempting to transfer a human mind into a machine, which is the direst tech-heresy imaginable.
The Unknown Heretic: An individual known only for hunting members of the Calixian Conclave and demonstrating an intimate knowledge of the workings of the Inquisition.

Others

Myrchella Sinderfell: A Scintillan noblewoman and the end result of a Recongregator experiment in genetic engineering gone horribly wrong. Has dabbled in every heresy imaginable, including warpcraft, and travels the sector indulging in continuous acts of wanton depravity.
Magos Vathek: A former Disciple of Thule obsessed with making zombies and other freaky shit.
The Burning Princess: An alpha-plus rogue psyker and pyromaniac who has escaped several attempts to capture her.
Coriolanus Vestra: A missionary turned heretic who was driven insane by the Tyrant Star in the Koronus Expanse.
Tobias Belasco: A Malfian noble and another product of the same experiment as Myrchella Sinderfell, with a similar appetite for depravity. Noted for being a cannibal. Active in the smuggling of xenos artifacts and human trafficking. On the run from both the Inquisition and his own family. Appears to be at least partially inspired by Baron Harkonnen.

Cults and Recidivists

Chaos Cults

Pilgrims of Hayte: A nihilist cult of Chaos Undivided from Malfi that exists mainly to wreck shit. Named after a Brother Cadfael novel.
Ateanism: A philosophy based on Keats' "Ode on a Grecian Urn" that turns its adherents into the pawns of Slaanesh.
Brotherhood of the Horned Darkness: Worshipers of Balphomael, who provides power, wealth and influence in exchange for human lives.
Menagerie: What you would get if the Joker formed a cult of Tzeentch. Dedicated to spreading madness throughout the sector through plays and carnivals. Particularly adept at absorbing other cults and organizations.

Other Cults

Temple Tendency: The remnants of the former Imperial Cult under Goge Vandire, which plots to overthrow the current Ministorum and reestablish dominance.
Night Cult: A splinter faction of a funerary cult centered in Maccabeus Quintus that trucks in reanimation and other forms of necromancy.

Other Heretical Organizations

Logicians: A technocratic organization united through progressive ideology and a desire to return to the Dark Age of Technology. Popular with hereteks for obvious reasons.
Pale Throng: A militant mutant-rights organization that spread throughout the Calixis Sector in the aftermath of the Tranch War.

Recidivist Organizations

Kasballica: The Space Mafia. Yeah, that pretty much covers it.
Serrated Query: An atheist, xenophile, Warp-using cartel. Extremely resourceful due to their freethinking mindset, willingness to experiment, and devotion to profit above all other concerns.
Amaranthine Syndicate: A seemingly legitimate trading organization that, in addition to its smuggling operations, is actually the pawn of a xenos species known as the Slaugth.
Beast House: A group of hunters and smugglers who traffic in xenos creatures, mainly for gladiatorial arenas and other blood sports.

Supplemental Books

As this is FFG's baby, it has the most supplemental books, although it has slowed down considerably in favor of the other 40k RPGs. With the arrival of Dark Heresy 2nd Ed., it's possible there will be no more splats for Dark Heresy.

Game Master's Kit - A GM screen with art on one side, and some handy notes on the other. Comes with a pre-written adventure and new rules for using poisons and toxins.
Purge the Unclean - Typical adventure splatbook, comes with three pre-written adventures that can run one into the other, or not. Gives insight in the shadowy nature of the Calixis sector.
The Inquisitor's Handbook - Almost essential once your campaign is underway. Provides a little bit of everything for everything, but the best part is getting character creation details for nuns with fucking guns.
Disciples of the Dark Gods - Splatbook that provides details on the various evil cults and rivalries within the Calixis sector, and includes a pre-written adventure revolving around said cults and rivalries. Also includes unique xenos species and adversaries, and expands on the Slaugth, previously introduced in the Game Masters Kit.
Creatures Anathema - Basic beast splatbook, but has good art and gives some options for xenos gear.
The Haarlock Legacy: Tattered Fates/Damned Cities/Dead Stars - A pre-written adventure spanning three books, it's fucking huge. Pretty interesting story, and surrounds FFG's take on the Harlock character from the anime Space Pirate Captain Harlock, aptly named Erasmus Haarlock. The three books are available together as a trilogy, but for whatever reason when you try to buy it looking through Dark Heresy's product page, it's unavailable. To buy it, just look for it through the Shop section of the FFG site. Also provides plot hooks for advancing the Calixis Sector setting, which will never be developed by FFG.
The Radical's Handbook - Splatbook that gives instruction on how to tread the thin line of the Inquisition and how not to. Adds in new alternate career paths, new heretical and xenos gear, and lots and lots of HERESY. Not to be confused with The Radical Handbook, about how to be cool in the '90s.
Ascension - Super useful supplement for taking your campaign to the next level. Adds in "ascended" ranks, or ranks 9-16. Acolytes leave behind their acolyte-ness and become Throne Agents, those actually trusted by the Inquisition. The new career ranks range from your murderhobo assassin actually becoming a Vindicare, or going straight to be the Inquisitor. Gives you skill and talent masteries, as well as making psychic powers even more prevalent (Time to rend the veil with Unnatural Willpower). Also adds in the influence talents, to represent the power your characters now hold. If you get only one DH supplement, get this one. Common consensus is that this splatbook is poorly balanced and breaks aspects of higher-level gameplay while remaining incompatible with higher-powered FFG games.
Blood of Martyrs - Rules on how to be even more pious and fanatical as you play as Adeptus Ministorum, or Ecclesiarchy, characters, and it redoes SoBs into their more Battle Sister counterparts. Gives you new alt. career ranks, backgrounds, and gear to help you purge the heretic.
The Apostasy Gambit: The Black Sepulchre/The Church of the Damned/The Chaos Commandment - Another fucking huge pre-written adventure spread across three splatbooks. Each book can be played together or separately, but it's pretty interesting to play them together. Somewhat controversial for advancing the official setting in grimdark/grimderp ways. The events are actually referenced in Only War, but only briefly.
Daemon Hunter - Gives you what it says, rules to play Ordo Malleus characters dedicated to killing daemons. Gives you all the background fluff and gear you'll need to play. The biggest pull of this book is that it finally adds in rules for including and playing Grey Knights in your campaign. (Be warned, if not carefully monitored, even one PC grey knight will fuck over your campaign and become the sole Mary Sue badass. Starting stats are 2d10 + 30? Really? With Ascension's Heroic and Mastery characteristic upgrades, a Grey Knight can top out at 80 in a stat just through character creation and buying characteristic advances.) Since this was printed after Deathwatch was released, it gives guidelines on playing as Grey Knights in a Deathwatch campaign and vice-versa.
Book of Judgement - Neato splatbook that contains rules on how to basically played Judge Dredd-esque campaign or story. It has new alternate career ranks, backgrounds, and careers for characters on the good or bad side of Imperial law. Comes with a pre-written adventure, Jurisdiction.
The Lathe Worlds - Likely the last splatbook for Dark Heresy 1e, it focuses on the tech worlds of the titular Lathe Worlds. The new rules, backgrounds, career ranks, and gear this book brings definitely is more focused on tech-priest characters, but not completely. Skitarii is OP and the book in general breaks the Techpriest class by making it capable of performing the functions of all the other classes. Has a pre-written adventure within as well. Possibly the last Dark Heresy supplement, what with the announcement of ~~Only War - Inquisitorial Paint Job Edition~~ Dark Heresy 2nd edition.