- BFS: One of the Assault subclass's specialties.
- Bling of War: Inquisitors are one of the best examples of this in the entire setting and Crusaders exemplify it.
- Expy Discount space marines, utilizing Powered Armor and chainswords. They also draw from the Imperial Guard-er, Astra Militarum, since they prefer stubbers and lasguns to Bolters.
- Knightly Sword and Shield: The Assault Crusader uses a supression shield and a chainsword, although the sword can be just as easily swapped for a pistol...
- Luckily, My Shield Will Protect Me: The other gear specialty of the Assault subclass.
- Macross Missile Massacre: One subclass has a Cyclone Missile Launcher as their special attack. This is a miniaturized Multiple Launch Assault System usually mounted on Space Marine Terminators.
- Mana Meter: The Crusader's ability resource is called "focus" and acts in the typical fashion, regenerating at a fixed rate over time.
- Powered Armor: The only class that has it.
- Sentry Gun: The Tactical subclass can call in a Tarantula bolter turret.
- Magic Staff: The Empyreanist subclass specializes in the use of a large Force Staff.
- Lovecraftian Superpower: As in the tabletop, psychic powers can have nasty backlash. In practice, the psyker's powers are subject to Overheating, and pushing them too far can actually cause daemons to spawn in.
- Magic Knight: Due to how Magic Is a Monster Magnet, they use guns and swords as much as they do their powers.
- Overheating: Using "heat" as a synonymn/slang for "attention" or "scrutiny." Using their powers attracts attention from daemons, and they can only use so much before they get possessed, flipped inside-out, or a combination of the two.
- Cyborg: While not as pronounced as most Tech Priests, he does possess several cybernetic limbs and a mouthpiece.
- The Minion Master: His main gimmick is that he can summon Servitors to aid him in battle, ranging from skittering spider-bots to hulking Kastallan Robots.
- Too Important to Walk: He exclusively moves around via a "walking pad", even when aboard the ship.
Ragna Van Wynter
The pilot of the Inquisitor's ship, and the last surviving member of her Rogue Trader house, which was purged after her father was convicted of smuggling heretical texts. Due to her piety, she alone was deemed worthy of redemption by the Conclave, and she serves as the Inquisitor's pilot as part of her penance.
- Sins of Our Fathers: Her entire House except her was put to death after her father was caught smuggling heretical texts in the sector. It later turns out that her father had been blackmailed into doing so by the Word Bearers.
- Undying Loyalty: Regardless of where you are Radical or Puritan, she will follow you willingly, especially if you overturn her House's conviction.
A Space Marine of the Stormwatchers Chapter, a Chapter focused on defending the Caligari Sector from threats both known and secret. He was originally part of Klosterheim's expedition to the Martyr, but was cut off from the Lord Inquisitor due to a Nurgle ambush and is ultimately crippled by a Helbrute. The Inquisitor helps him get healed in order to learn more about Klosterheim's mission, and afterwards he sticks around to serve as the organizer for Inquisitor combat training.
- Blood Knight: As a Space Marine, he naturally has a fondness for combat, especially against Chaos Marines. Fittingly, he is more often than not your Mission Control for Purge missions.
- But Thou Must!: After he defies your orders by storming the Khorne-infested Stormwatcher outpost, even if you choose the Puritan option to punish him, you don't actually kill him due to the inherent value of having a Space Marine in your crew.
- Can't Kill You, Still Need You: On the receiving end of this by Puritan Inquisitors at the end of the first leg of the Khorne DLC. Defying a superior's orders as he did would be an instant death sentence in literally any other situation in the Imperium, but because he's an experienced Space Marine, the Puritan Inquisitor grudgingly spares his life and allows him to remain aboard, but firmly tells him he is on his very last warning.
- A Day in the Limelight: He gets increased focus in the free Khorne DLC due to the DLC's revelations regarding his Chapter's origins and past.
- I Owe You My Life: Presumably why he sticks around in your retinue even after Metrodora heals him. Becomes much more explicit if you forgive his disobedience during the Khorne campaign.
Metrodora ThelemaA Magos Biologis of the Adeptus Mechanicus who specializes in researching the various Nurglite plagues. The Inquisitor seeks her out to have her heal Caius Thorn after he is brutalized by a Helbrute, and afterwards she decides to fully join the Inquisitor's crew. She allows you to customize your Inoculators.
- Dark and Troubled Past: The free Dark Eldar DLC reveals that when she was young, a Dark Eldar raiding party slaughtered her colony and abducted her, using her as a lab rat for their drugs and poisons before being rescued by a Mechanicus strike team. Ever since, she has harbored a seething hatred for the Drukhari.
- A Day in the Limelight: Receives considerable focus in the Dark Eldar campaign.
- Fantastic Racism: As explained in Dark and Troubled Past above, she really hates the Dark Eldar.
A Mechanicus Tech Priest and proud member of the Xenarites, a subfaction of the Mechanicus that believes that Xenos technology should be studied and preserved, not destroyed as Mechanicus doctrine demands. He was kidnapped by the Feral Beasts mercenary company as part of Klosterheim covering up his search for the Martyr, and the Inquisitor rescues him in order to learn more about Uther's Tarot. Afterwards, he joins the Inquisitor's crew as a gear crafter.
- The Heretic: Averted, but only barely. By his very nature as a Xenarite, his actions and beliefs dangerously toe the line between acceptable and heresy, something the Inquisitor dryly comments on throughout the game.
- Escort Mission: Twice! First you have to escort him through the Feral Beasts base after rescuing him from his cell, then later you have to protect him while he interfaces with the Martyr's Machine Spirit.
- Lack of Empathy: He sheds absolutely no tears over the fate of the Nurgle Daemonhost in his order's vault, even after a horrified Inquisitor explains that a Daemonhost's soul is damned to an eternity of suffering upon death. He claims its because his "empathy module" is broken.
- Mission Control: He serves as your primary operator and assistant during the final stages of the main campaign.
- Not So Stoic: He spends almost the entirety of the game borderline emotionless, but suddenly flies into a rage during the battle against a Chaos Knight towards the end of the Khorne campaign, furiously declaring it a blasphemy against the Omnissiah.
The Chaos God of disease, decay and poison. His forces occupied the Martyr long ago, and now his Daemons and Cultists run rampant throughout not just the returned Fortress Monastery, but the entire Sector.
- Affably Evil: Just like in canon, the Plague Marines are shown to be surprisingly jovial and cordial despite being just as willing to kill you as any other Chaos Marine.
- Asteroids Monster: Reborn Marauders explode into Toxic Entities upon death.
- Body Horror: As one would expect from Nurgle, his cultists are covered in huge, cancerous growths and tumors. The Daemonhosts are by far the worst in this regard.
- Final Boss: A Great Unclean One serves as the final boss of the main campaign. Its heavily implied that it is the entity Uther Tiberius made a deal with in order to create the Alpha Pariah.
- Greater-Scope Villain: Nurgle is this to the main campaign, as his cultists and Daemons are the main antagonistic force in it.
The Word Bearers
The Traitor Legion of Lorgar, and one of the few Traitor Legions who swear fealty to Chaos Undivided instead of a single God. They are first encountered in the depths of the Martyr, seeking Uther Tiberius' secret based on an ancient prophecy they uncovered.
- Human Sacrifice: Their role in the Chaos Undivided campaign involves them having their mutant cultists perform mass abductions for a sacrificial ritual.
- Elite Mooks: All of them are considered Champion-class enemies.
- Evil vs. Evil: They seem to utterly loath the Voidrippers, and the plot of the Khorne campaign is in fact kickstarted by them raiding an Inquisitorial data vault in order to find their hideout so they can go and slaughter them.
- Starter Villain: While not the first enemy force you encounter, they are the first Chaos Marine faction you are likely to encounter in the game.
The Alpha Legion
The Traitor Legion of Alpharius and Omegon, and by far the most enigmatic of the Traitor Legions.
- Cold Sniper: One of their units is a Sniper who can shave off tons of your health and suppression with a single shot.
- Talkative Loon: True to canon lore, the Champion you face at the end of their portion of the Chaos Undivided campaign talks primarily in cryptic riddles and confusing phrases.
- You Have Outlived Your Usefulness: Towards the end of their portion of the Chaos Undivided campaign, you can come across the "prophet" they were using to stoke rebellion in the system, having been transformed into a mindless Chaos Spawn.
The Black Legion
The Traitor Legion of the Arch-Traitor, Horus Luprecal, currently under the command of Abbadon the Despoiler.
- Deadpan Snarker: The Black Legion Champion who serves as the Final Boss of the Chaos Undivided campaign is shown to have just as much of a dry wit as the Inquisitor themselves.
- Deflector Shield: Their Marines are among the only enemies in the game who make use of shields.
- Elite Mooks: They are among the most advanced enemy factions in the game, with even their bog standard cultists being much more dangerous than the others.
- Legion of Doom: The free Chaos Undivided DLC involves them forming an alliance with the Word Bearers and Alpha Legion in order to destabilize the Caligari Sector so Abbadon can conquer it.
- Zerg Rush: Played with. While they can use Gobbler Cultists as Horde enemies like the other Traitor Legions, they rarely do so, instead preferring to use the considerably more durable Chaos Spawn as their "swarm" units.
The Kabal of the Jagged Maze
A Dark Eldar Kabal that has been operating in the Caligari Sector for centuries. When the Triglav Subsector was cut off from the rest of the Sector decades ago, the Kabal swooped in and completely took over, enthralling most of the Subsector's military and governing powers to their will and using the pain and agony of the rest to power devices called "Pain Catalysts", which use the pain of the Dark Eldar's victims to grant them great power.
- Berserk Button: the Succubus that serves as the Arc Villain for the first act of the Dark Eldar DLC becomes livid when the Inquisitor points out that she and all other Dark Eldar are simply delaying the inevitable in regards to Slaanesh claiming their souls.
- Crazy-Prepared: In the first act of the Dark Eldar DLC, they always seem to be one step ahead of the Inquisitor, constantly being able to predict their movements and always knowing exactly where they are. This is ultimately revealed to be through the use of a rogue Psyker they Mind Raped into servitude.
- Defiant to the End: By the time the Inquisitor raids their main base, the Kabal's control over the Triglav Subsector has been all but shattered and most of their leadership is dead. Nevertheless, they fight to the end to defend the remaining Pain Catalysts.
- Fantastic Drug: "Euphoria", a hallucinogenic that the Kabal uses to bend mortals to their will.
- King Mook: The Pain Engine that serves as the Final Boss of their DLC, the Demented, is essentially a giant, souped up Talos.
Nurgle is no longer the only Chaos God with his eyes on the Conclave, as now the Blood God also turns his gaze in its direction. His primary agents in the Caligari Sector are the Voidrippers, a Chaos Marine Chapter that shares a dark history with the Stormwatchers.
- Bloodier and Gorier: Khornate enemies let out an explosion of blood when killed. Khorne wouldn't have it any other way.
- Mad Bomber: The Voidripper Possessed are like the Havocs used by the other Chaos Marines, except that in addition to the standard grenades, they also attack with cluster bombs and extremely damaging mines.
- Fallen Hero: The Voidrippers turn out to be Stormwatchers who succumbed to their innate bloodlust and fell to Khorne.
Hive Fleet Garm
A Tyranid Hive Fleet that attacked the Caligari Sector decades ago. Thanks to the efforts of the local branch of the Mechanicum, the Hive Fleet was largely destroyed, but numerous Tendrils survived and continue to ravage any world they can find.
- Action Bomb: Spore Mines will explode for high damage if they get too close.
- Horde of Alien Locusts: As one would expect from Tyranids, their sole desire is to devour worlds and use its biomass to create more of themselves. However, this game-exclusive Tyranid Hive Fleet Garm is this trope more than other Tyranid Hive Fleets. They consumed numerous worlds before they were stopped. However, the Hive Fleet realised their defeat was inevitable and that full-scale invasions wouldn't work, so instead use all their remaining biomass to infect as many worlds as possible with Tyranid life-forms. Even after a lot of these worlds were purged, more still remain, worlds that were considered "purged" have Tyranids return, and on one planet the local Tyranids even survived Exterminatus by hiding underground. Certain Clues and mission dialogue, as well as "the Savant" tech-priest, express the worry that the Tyranid Forces was just a probing action of the Hive Fleet Garm, explaining their resurgent nature on worlds thought purged of Tyranids life forms, and that the Hive Fleet will soon return with far, far greater numbers against the planets that have been weakened by the constant local Tyranid infestations.
- Starter Villain: They are the first enemy faction encountered by Tech-Adept Inquisitors.
For centuries, the Eldar of Crafworld Tualthe existed in relative, but tense peace with the Caligari Conclave, but this all changed when the Craftworld became infected with Chaos with no hope of a cure, causing it to slowly but surely die. In desperation, the Eldar attempted to migrate to one of their Maiden Worlds, only for it to be subjected to Exterminatus as part of the Mechanicum's efforts against the Tyranids of Hive Fleet Garm. Ever since, the Eldar of Tualthe have held a bitter grudge against the "mon-keigh", and now desperately search for a way to save their dying Craftworld.
- Badass Biker: One of their Champion variants utilizes a large landspeeder in combat.
- Fantastic Racism: Eldar by and large view the "mon-keigh" of the Imperium as upstart children even in the best of times, but the loss of their Maiden World has made the Tualthe Eldar considerably more openly hostile towards Humans.
- Friendly Enemy: Farseer Mereth is shown to be rather cordial and friendly compared to the dispassionate indifference and/or disdain most Eldar have towards Humanity. He even gives you some vital information regarding your mission before he dies after you defeat him.
- Glass Cannon: Much like their Drukhari cousins, they specialize in high damage but little defense.
- Magic Knight: Farseers are just as capable in physical combat as they are in magical.
- Moral Myopia: The alternative to having their Maiden World glassed was to let the tyranids eat it, grow stronger, and guzzle up the whole sector. They're still salty about the nasty primitives nuking their pretty planet.
One of the most infamous known Chaos Marine and the premiere Mad Scientist of the galaxy. He has traveled to the Caligari Sector in order to claim Uther Tiberius' secret weapon as his own, which quickly brings him into conflict with the Inquisitor.
- Actually a Doombot: His tendency to mass produce clones of himself is acknowledged by your Inquisitor, who isn't even sure if the Bile you encounter throughout Prophecy is even the original, "true" one. Considering Prophecy ends with his death, its safe to assume he was a clone.
- Batman Gambit: Upon learning that an Inquisitor has taken the Alpha Pariah into their custody, he unleashes a Nurglite plague on a Hive World in order to lure Inquisitors to him until he finds her.
- The Friend No One Likes: A lore entry makes it clear that the Plague Marines assigned as his bodyguards can't stand him and are itching for an excuse to turn on him. This is true to the lore of the setting, as Bile's refusal to swear fealty to any of the Chaos Gods, as well as his casual disregard for the lives of his followers, makes him very unpopular amongst the Traitor Legions.
- Hopeless Boss Fight: Even if you're one of the vanilla Inquisitor classes and are at level 50+, the first encounter with Bile can't be won.
- Labcoat of Science and Medicine: One which we are contractually obligated to remind you is made of human skin.
- Mad Scientist: Its Fabius Bile, what else would he be?
- One-Winged Angel: Transforms into a Greater Chaos Spawn partway through the final battle of Prophecy.
- Voice of the Legion: All Chaos Marines have this, but Bile's stands out due to how guttural and outright demonic it sounds even in comparison to the Traitor Legions ingame.
- Apocalypse Maiden: As everyone who is in the know puts it, she could either be the greatest hero the Imperium has ever known since the God-Emperor, she could become the fifth Chaos God and finally end the galaxy, or she could amount to nothing at all.
- Badass Adorable: She has been kept in stasis for centuries and appears relatively young, despite her overwhelming psychic power.
- Macguffin Girl: Everyone in the Caligari Sector wants her. The Puritans want to execute or contain her as they believe she's too much of a potential threat to be left alone, Klosterheim and the Radicals want to mold her into the ultimate weapon against Chaos, the Word Bearers (and presumably the rest of the forces of Chaos) want her because they believe she's central to a prophecy foretelling Chaos' ultimate victory against the Imperium, both the Dark and Craftworld Eldar want to use her powers to save their respective factions, and finally, Fabius freaking Bile wants her because he believes she "rightfully" belongs to him due to how Uther Tiberius used his research to create her.
- Only Sane Man: For someone living in the Warhammer 40K universe, she has an outlook on the galaxy that is similar to what would be actually acceptable 10,000 years prior. Partially justified, as she has been kept in stasis for millenia. The other implications could create theses as long as the Administorum's daily quota.
- Physical God: The Alpha-Pariah has the power to eat demon souls. This means she can kill demons for good, and will help the Inquisitor permanently kill a Greater Daemon, something considered near-impossible.