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Literature / Eisenhorn

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All my life I have had a reputation for being cold, unfeeling. Some have called me heartless, ruthless, even cruel. I am not. I am not beyond emotional response or compassion. But I possess - and my masters count this as perhaps my paramount virtue - a singular force of will. Throughout my career it has served me well to draw on this facility and steel myself, unflinching, at all that this wretched galaxy can throw at me. To feel pain or fear or grief is to allow myself a luxury I cannot afford.
Gregor Eisenhorn, 240.M41

Eisenhorn is a trilogy of novels by Dan Abnett set in the Warhammer 40,000 universe, following the adventures of Inquisitor Eisenhorn and his retinue as they combat the enemies of the Imperium of Man. Throughout the books, Eisenhorn finds himself having to use increasingly desperate and dangerous means against his foes.

The first book, Xenos, starts with Gregor Eisenhorn and his crew pursuing a heretic in a seemingly routine task when they uncover a mysterious artifact bearing the preserved mind of the heretic Pontius Glaw. In the subsequent investigation, Eisenhorn and crew find themselves embroiled in a heretic group's plan to contact aliens for a daemonic text.

The second book, Malleus, begins with a major celebratory parade ruined by Chaos-linked renegades. The pursuit of these enemies leads to Eisenhorn uncovering and defeating a much-revered Inquisitor gone to Chaos.

The third book, Hereticus, sees Eisenhorn pursued by allies of Glaw and his attempt to stop Glaw from acquiring a world-ending power.

The fourth book, The Magos, is set between the Ravenor and Pariah Trilogies, and serves to bridge Eisenhorn's role between the two. Unlike the previous 3 books, it isn't a first person narrative and predominately focuses on the character of Magos Drusher, a bystander dragged into a case by Eisenhorn himself.

There are also several short stories available, two of which can be found in the doorstopping omnibus edition. The series is followed by the Ravenor and Bequin trilogies.

Eisenhorn also appeared in a the set of Audio Dramas, collectively called Talon and Thorn.

A video game adaptation of Xenos, developed by Pixel Hero Games, was released on August 8, 2016. A live-action television adaptation from the showrunner behind The Man in the High Castle is in development.

As part of Warhammer 40,000, the series involves a large number of the tropes on that page, as well as employing literary and narrative tropes of its own:

  • Adventurer Archaeologist: A villainous example is a minor character in Xenos, though more of a Punch-Clock Villain.
  • Aliens Are Bastards: The Saruthi, from Xenos, were initially a benign species, until they were exposed to a Chaos artifact that fundamentally altered their entire species on a genetic level. They have become hideous, disturbingly asymmetrical creatures who enjoy torture and enslaving sentient life forms, and who intentionally create architecture that bends space and time to drive humans insane just through proximity.
  • Alien Geometries: The saruthi "tetrascapes" in Xenos, and in a different way, the world of Ghul in Hereticus.
  • All Your Base Are Belong to Us: In Hereticus, masked mercenaries raid Eisenhorn’s estate on Gudrun, and he barely makes it out alive alongside Aemos, Medea and Eleena Koi. He later learns that this was part of a simultaneous, coordinated strike against all his agents and holdings throughout the sector.
  • And I Must Scream:
    • Ravenor, as a result of the Thracian Gate massacre in Malleus. He's basically the main character in Johnny Got His Gun, except that his psyker ability allows him to function through his force chair.
    • Pontius Glaw until Eisenhorn (perhaps foolishly) has a body built for him.
  • Anyone Can Die: By the end of Hereticus, much of the main cast are either dead or severely incapacitated.
  • Armour Is Useless: Unusually for this setting; it saves someone's life only once in the trilogy.
  • Auction of Evil: In Malleus, Eisenhorn infiltrates a clandestine slave auction where one of the villains is selling an Alpha-plus level psyker. The villain doesn’t actually intend to sell the psyker, however, and is using the auction to flush out anyone that might be on his tail. Eisenhorn realizes this, and comes prepared. The other buyers don’t, and end up slaughtered by the villain’s minions.
  • Badass Cape: Pontius Glaw, in the final encounter with him, wears one made of many small, very sharp blades.
  • Badass Longcoat: Eisenhorn is fond of billowing overcoats, although, cover picture be damned, he's never actually mentioned as wearing two at once.
  • Badass Normal: Valentin Drusher; a Magos Biologis without any combat training, special abilities, or overt physical capabilities.
  • Beast Man: Some of the mutants that Eisenhorn encounters on Eechan look like anthropomorphic animals. The mutant crimelord Phant Mastik looks like a grotesque anthropomorphic elephant.
  • Beauty Is Never Tarnished: Alisebeth Bequin, who manages to be glamorous and alluring even while exchanging gunfire with enemy heretics and brain dead.
  • Belly Mouth: In Malleus, there’s a mutant erotic dancer with a grinning mouth where her navel should be.
  • Bittersweet Ending: Pontius Glaw's apocalyptic plan is foiled, but only after most of Eisenhorn's friends have been killed in the process and his entire network has been dismantled. Eisenhorn himself just barely manages to avoid being declared a heretic and keep the existence of Cherubael under wraps, but is also left physically crippled by the injuries he sustained on his journey. Whether or not he'll manage to keep from falling further in to corruption without his friends to act as his moral compass any longer is anyone's guess.
  • Brown Note: The utter, incomprehensible scale of the daemon-king's tomb on Ghul in Hereticus drives a hired gun to tears.
    • In Malleus being an ordinary human attending the parade...
    • In Hereticus, the Chaos Titan has dirge casters that blast infrasound onto the battlefield. For reference, infrasound is a noise that inspires unfounded fear, dread, and paranoia in those that hear it.
  • Camp Straight: Rogue Trader Tobias Maxilla. A flamboyant dandy, he flirts with every woman he encounters. Somewhat ambiguous; he is implied to be a machine fetishist, perhaps exclusively.
  • Canon Welding: With the release of The Magos collection, a number of elements from unrelated stories by the same author was hammered into the Eisenhorn canon, culminating in the eponymous novel which turned the Eisenhorn trilogy into a tetralogy. Most notable was the Magos Dusher short stories, which was described by Abnett as "CSI: 40k." Indeed, if Drusher isn't the outright protagonist of the The Magos novel, then he's the Deuteragonist and main observer of Eisenhorn as the Non P.O.V. Protagonist of that story.
  • Captured Super-Entity: The Psykers whose kidnappers were responsible for the Thracian Gate atrocity in Malleus. Also, the daemonhosts Cherubael and Prophaniti, to an extent.
  • The Chessmaster: Both Big Bads fall handily into this. Eisenhorn himself flirts with the trope; in many ways, he is like a Cold War spymaster, only with Psychic Powers and a way with a sword.
  • Clear My Name: Pretty much the entire plot of Malleus. Eisenhorn is (perhaps reasonably} finds himself declared a radical, though finds himself imprisoned and interrogated by the Lord Inquisitor Osma and his minions. Under the circumstances (unreasonably) Osma is willing to face the embarrassment and censure if Gregor, being a still fairly Puritan and innocent inquisitor, is found to be the mastermind behind the Thracian atrocity.
  • Cold-Blooded Torture: Eisenhorn suffers this at the hands of the Glaw family, which ends with the nerves in his face being irreversibly paralyzed and leaving him a Perpetual Frowner.
  • Combat Pragmatist: Eisenhorn starts a pointless swordfight, then shoots his opponent when he starts to lose.
  • Come to Gawk: The parade included displaying captives from the latest Imperial crusade, purely for propaganda purposes.
  • Compelling Voice: Eisenhorn and other Inquisitors, through what Eisenhorn refers to as "the will", a manifestation of their psyker abilities. Agents of Chaos display this power as well.
  • Continuity Drift:
    • At one point Eisenhorn mentions the "Primarch" of the White Consuls, by which he clearly means the "Chapter Master", but the distinction was less well established in canon back when Malleus was written, or possibly Eisenhorn just didn't know better in character (subsequent editions and audios just reference the White Consuls, in context).
    • Also, Aemos twice mentions Tyranids in passing, while Ravenor would reveal that both stories took place before they were named or (officially) encountered.
  • Continuity Nod:
    • Inquisitors Heldane and Ravenor both appear in Abnett's earlier Gaunt's Ghosts novels. Titan Princeps Hekate (from the Graphic Novel series Titan) is also mentioned in Malleus, albeit as an old man near retirement, which was a pleasant surprise for fans, as his own series by that point seemed to have ended in a Heroic Sacrifice.
    • One of Battlefleet Scarus' ships is named Defence of Stalinvast, after the planet subjected to Exterminatus in Ian Watson's Inquisition War Trilogy.
    • Another in Malleus. Eisenhorn mentions his plans to meet with a group of other Inquisitors, one of which includes Defay, presumably the same from the Inquisitor comic series in Warhammer Monthly.
  • Cool Old Guy: Eisenhorn himself. He is in his 40's when first introduced, which is still late for the average human but no age at all for resourced Imperial citizens and servants, who have access to Juvenat treatments which can extend the lifespan to several centuries. By the end of the third book he is still active at over 180 years old. By the time of the Eisenhorn vs. Ravenor he is nearly 300 years old and, though physically a wreck, more dangerous than ever.
  • Cool Old Lady: Inquisitor-General Neve, the commander of the Ordos Cadia in Malleus. She's a blunt, cantankerous woman in her late 110s, and generally highly unwelcoming to Eisenhorn and his team - especially when she thinks they're investigating an inconsequential case while she "has a hundred active cults to subdue every month!". But, she's an active fighter despite her crippling limp, has a grenade launcher built into her cane, and is willing to listen when Eisenhorn shows her evidence about how serious his investigation is.
  • Crapsack World: For the most part averted. Although Eisenhorn visits many deeply unpleasant places during his adventures, this must be taken in context with the larger Warhammer 40K universe. Yes, there is still galaxy spanning war going on, but Imperial society is shown as functioning and, in the case of the planet Gudrun, can be extremely pleasant or at least tolerable.
    • Taken straight with Hive Worlds like Thracian Primaris and Sameter.
  • Cross-Melting Aura:
    • The Chaos-corrupted Battle Titan Cruor Vult in Hereticus has such great psychic presence that it goes right through Bequin's blankness and destroys her mind.
    • Cherubael does this to an Imperial aquila.
  • Cryonics Failure: The opening to Xeno features this on a large scale; in an attempt to slow down Eisenhorn, Eyclone prematurely triggers the defrosting process in a vast cryogenics facility housing the nobility of Hubris (who traditionally enter cryrosleep to wait out their world's eleven-month-long winters). Without medical staff present to help them, thousands of people suffer deadly freezer burns, are trapped in caskets, or are slaughtered in the crossfire as they stumble around blinded by their improper revival.
  • Dropped a Bridge on Him: Midas Betancore gets this treatment between Xenos and Malleus. So does Nathum Inshabel, and his entire staff between Malleus and Hereticus.
  • Dug Too Deep: In Malleus, the miners of Cinchare dug up an evil sentient rock which promptly enslaved the whole colony with its psychic powers.
  • Eldritch Location: Saruthi tetrascapes. In the coastal regions of a tetrascape, waves on a shoreline break backwards, and that is the least weird thing about them.
    • It's implied that the Saruthi intended them to be unnerving, as they were created for the aliens to meet and bargain with other races—the Saruthi wanted to intimidate visitors to establish that they were in control.
  • Empathic Weapon: Eisenhorn's force sword, Barbarisater. Not to mention that it's technically stolen from the home of his acolyte Arianhrod's homeworld, it's a mastercrafted weapon reforged into a force sword with hexagrammatic runes, and it has a limited will of its own, encouraging Gregor to use certain moves and seemingly controlling itself at certain points, but he also uses it as an effective dousing rod to sniff out Chaotic taint. Gregor thinks it allowed itself to be broken to end a life-or-death duel at one point, necessitating it to be repaired from a longsword into a rapier weapon.
  • Enfant Terrible: In Malleus, one of the escaped Alpha-plus psykers is a child. It telepathically forces Eisenhorn to kill a Space Marine and then himself, laughing at his struggles all the while.
  • Evil Is Deathly Cold: Frost formation often accompanies use of Warp powers.
  • Extra Eyes: Nayl disguises himself as a mutant with fourteen extra eyes in order to infiltrate a club for mutants.
  • Eyeless Face: The mutant nightclub that Eisenhorn and Nayl infiltrate features an erotic dancer with no eyes.
  • Eyes Do Not Belong There: In Malleus, they must infiltrate muties. One mutant woman winks at them — with an eye at the end of her tongue.
  • Faceless Eye: Malleus features a mutant with a giant eyeball for a head, with his mouth located elsewhere.
  • Faux Affably Evil: Pontius Glaw is a charming, erudite, and refined gentleman. Eisenhorn notes that were he not also Chaos-corrupted, the two of them would probably have been the best of friends.
  • Fed to the Beast: The Glaws try to dispose of Eisenhorn and his associates by throwing them into an arena with two hungry carnodons. They foolishly provided Eisenhorn’s team with weapons, enabling them to kill one carnodon and release the other from its chains so it can rampage through the audience.
  • Friendly Enemy: Cherubael to Eisenhorn, at least at first, because Eisenhorn can free him from his servitude to Quixos. He becomes much less friendly (and somewhat less of an enemy) later on, after Eisenhorn re-binds him and sticks him in storage, occasionally pulling him out to battle powerful opponents.
  • Frozen Face: Eisenhorn is left unable to make any kind of facial expression after the extensive neurological damage he suffers during Locke's Cold-Blooded Torture. As of The Magos not anymore.
    • Though strangely, even though he smiles at the end of The Magos, in Pariah (which chronologically takes place after The Magos) Beta distinctly notes and comments on the fact that Eisenhorn's face shows no emotion at all, not even micro-expressions, and he agrees with her. In a few occasions in Penitent, Eisenhorn does make some expressions, a call back to The Magos. Justifiable in that after decades of not being able to make any expressions, the muscles need to be retrained.
  • Full-Frontal Assault: Cherubael and Prophaniti.
  • Generation Xerox: "So very Betancore... Just like her damned father." The title for that chapter is "Something Typically Betancore."
  • Ghost Town: In Malleus, Eisenhorn visits the mining colony of Cinchare to check up on an old acquaintance, but finds the town strangely deserted. The few people still around claim that the mining companies pulled out after an outbreak of disease ravaged the population. In reality, a sentient evil rock had enslaved the colony and fused the missing colonists together into a giant flesh worm.
  • Gladiator Games: Eisenhorn and company are forced into one.
  • Glamour Failure: The Daemon-possessed suffer from this.
  • Godzilla Threshold: Eisenhorn summons Cherubael, breaking its bindings to do so, when faced with Fayde Thuring at the controls of a Chaos Titan and he has nothing that can even scratch the thing's paint. He then has to bind Cherubael into the nearest convenient body with impromptu binding sigils to save his own neck.
  • Guns Akimbo: Midas and Medea Betancore fight with a pair of needle pistols, and Interrogator Inshabel is armed with a pair of laspistols.
  • He Who Fights Monsters: Eisenhorn falls into this rather badly, starting out as a staunch Puritan Inquisitor unwilling to accept that using Chaos against itself is a viable strategy. A combination of compromise and desperation, however, eventually leads him to conceal, protect and learn from an Arch-Heretic, engage in Warp Sorcery and summon a Daemonhost of his own. Ravenor is of the opinion that Radicalism is inevitable for Inquisitors, and the only hope for them is to do as much good as they can and hope they die before Jumping Off the Slippery Slope.
    • Harlon Nayl puts an interesting spin on the concept. He tells Eisenhorn that sometimes you've got to bend and break the rules in order to win. Eisenhorn assumes that this is equivalent to "the end justifies the means". Nayl denies this, noting that confusing the two is what leads to the slippery slope.
      • Fridge Brilliance kicks in when you realize that both of them are trying to self-justify. The series gives us several Inquisitors of long service measured in centuries who don't turn Radical, such as Rorken, Voke, Bezier, Neve and Ricci.
  • Hidden Villain: Although she isn't mentioned until the Ravenor series, Lilean Chase of the Cognitae is almost an overarching one for the entire series. Eisenhorn spends a great deal of time trying to track her down, unsuccessfully.
  • His Name Is...: In Malleus, Eisenhorn corners Lyko and probes his mind for the identity of the elusive mastermind behind the Thracian Atrocity. He’s just about to unlock the secret when Cherubael telekinetically flings Lyko into a combine harvester.
  • Honor Before Reason: Eisenhorn on a several occasions, most notably honoring an agreement to build a new body for the dangerous heretic Glaw and rebinding Cherubael into a new daemonhost just because he couldn't stand the fact that he'd been manipulated into returning Cherubael to the warp. Both end up biting him in the ass in a major way.
  • Hooker with a Heart of Gold: Bequin when we first meet her.
  • Humongous Mecha:
    • In Malleus, several Titans take part in the victory parade at Thracian Primaris. When possessed fighter jets start strafing the crowd, these Titans open fire in an effort to neutralize the threat.
    • In Hereticus, the heretic Fayde Thuring surprises Eisenhorn with a reactivated Chaos Titan.
  • Impaled with Extreme Prejudice:
    • In Xenos, an explosion hurls part of an axle-rod through Oberon Glaw’s skull.
    • In Malleus, Inquisitor Roban is fatally skewered by a forklift servitor.
  • Involuntary Suicide Mechanism: A captured mercenary has a Your Head Asplode variant of this that goes off when Eisenhorn attempts to interrogate him.
    • Later on, after Eisenhorn has been captured, he tries dropping the same phrase that made the lackey die when in the presence of the higher-ups. He didn't expect it to work, and was right.
  • "It" Is Dehumanizing: Eisenhorn refers to Cherubael as an "it" while others identify him as a male. As daemons are made from the psychic manifestations of sapient beings, they can develop a dominant gender identity. However, being buddy buddy with demons is a good way to let your guard down and have your soul consumed, so the trope is justified. When Eisenhorn starts referring to to Cherubael as a "he" in the Ravenor series, the titular character starts to get a little leery. Eisenhorn claims that Cherubael and he came to an understanding, leaving it ambiguous to whether or not Eisenhorn has fallen or not.
  • It's All About Me: Cherubael.
  • Karma Houdini Warranty: Osma brings allegations against Eisenhorn in Malleus that force him to go rogue, never being punished after the allegations are refuted and even being elected master. He gets himself killed at the end of Hereticus.
  • Laser Blade: Eisenhorn initially owned one of the extremely rare pure energy blade power swords before he wrecked it in combat in the second book.
  • Lawful Stupid: You'd be astonished how easily Inquisitors get caught by this, and others nominally charged with similar lines of work.
    • And Christ, does the Witchfinder in Malleus fall under here. His first appearance is him trying to execute Eisenhorn for heresy (though saving his life in the process) on absurdly tenuous charges. Eisenhorn shortly thereafter recounts a mission where twenty-odd newly discovered psykers, all under 14 years old, were abducted by raiders before the Black Ships could pick them up. Seeing that psykers are extremely rare and valuable, and even rarer to find at such young ages (since most young psykers get killed quickly by their talents), Eisenhorn launches a mission to rescue them while the Witchfinder decides that the kidnapping (that they had no control over) classifies them all as witches that are in dire need of execution.
      • Not only are psykers very uncommon but the reason that the Imperium sends Black Ships to collect them in the first place is because they're literally necessary for the Imperium to continue functioning. They're distinctly worth rescuing for all sorts of warm and cold hearted reasons.
  • Light Is Not Good: In Hereticus, Cherubael, who makes himself look like an angel of the Emperor on purpose just to mess with mortals further, invoking Pure Is Not Good as well. Eisenhorn lampshades it.
  • Living Legend: Commodus Voke - Eisenhorn describes his psychic powers as "legendary". He even stands up to a daemonhost and saves Eisenhorn's life.
  • Magical Camera: In the short story Backcloth for a Crown Additional, a nobleman dies two days after having his picture taken at a traveling fair. Eisenhorn looks into it and discovers that the photographer’s camera is tainted by Chaos, killing anyone whose picture he takes.
  • Mechanical Abomination: In Hereticus, the Cruor Vult is a Chaos-corrupted Battle Titan. It’s sixty meters tall, weighs two and a half thousand tonnes, packs enough firepower to obliterate a city, and has a psychic presence so great that it overwhelms Eisenhorn’s party with mental feedback just by coming online. When Eisenhorn tries to shut it down by exposing the Titan’s mind to Bequin’s blankness, the sheer force of its personality negates her blankness and destroys her mind.
  • Mental World: In Hereticus, Eisenhorn and Rassi enter the mindscape of the Chaos Titan Cruor Vult. It’s depicted as an endless sea of black sludge under roiling clouds of blowflies, with an effigy of the Titan itself standing at the very center. As they draw closer to it, they’re harassed by daemonic figures and bombarded with the Titan’s memories until they find themselves standing in its cockpit, where overlapping phantasms of its previous commanders sit on its command throne simultaneously.
  • Mercy Kill: Invoked and subverted as Eisenhorn explains why he could not do it to the dying victims at the opening of Xenos. Although the nobles of Hubris are in horrible pain and as good as dead anyways, Eisenhorn knows that if he shoots even a single one of them to quell their misery, he could face months or years of bureaucratic paperwork from the Hubris government that would give his enemies time to escape his grasp in the long run, and he doesn't like invoking his Inquistorial authority to bypass laws and customs... so he just leaves the nobles to die painfully instead.
  • Minor Crime Reveals Major Plot: Done as only 40K can do it. The first chapter has Eisenhorn hunting a traitor with thousands of murders on his record, not to mention innumerably more acts of smuggling, sabotage, and theft, who is nevertheless only a tiny cog in the grand scheme. It gets much bigger from there.
  • No Body Left Behind: In Malleus, Inquisitor Lyko incinerates the rogue psyker Esarhaddon with a plasma gun, leaving nothing but a pair of feet behind. When Interrogator Inshabel examines the feet later on, he discovers that the person Lyko killed wasn’t Esarhaddon, and realizes that Lyko faked the psyker’s death.
  • No Good Deed Goes Unpunished: Eisenhorn arranges for Pontius Glaw to be given a mechanical body in return for his guidance on how to create a daemonhost. This turns out to be a very, very, VERY bad move.
    • A milder example in the audio dramas. Master Immus, a clerk who has been used as a pawn in a heretical scheme, goes to a young Eisenhorn and confesses. After a long night of interrogation and mild mind rape, Eisenhorn comes to the conclusion that Master Immus is completely innocent of any involvement in the scheme and is grateful that a man did his Imperial duty by coming forward. The sentiment is decidedly one sided though because it results in the man's place of work being permanently shut down, leaving every employee there without a reference or any means of social support.
  • N-Word Privileges: Mutants call themselves "twists."
  • Obviously Evil: Discussed in-story with regards to the Necroteuch and Malus Codicium. The Necroteuch is obviously dangerous from the get-go, as it's sentient and overtly attempts to take control of its holder's mind and force their submission to Chaos. The Malus Codicium, on the other hand, is just a small black book. A nondescript, unremarkable book that one might find anywhere. Over the course of the series, Eisenhorn starts getting paranoid that the Malus Codicium may also sentient and, if so, is exerting its influence much more discreetly. Naturally the latter is much more dangerous.
  • Once More, with Clarity: In Hereticus, Eisenhorn and Ravenor hold an auto-seance to see what Pontius Glaw was up to on a planet. They watch a scene with him and an ogryn and a man with an auphex, but they can't tell what they are doing. Eisenhorn tells the astropaths to expand the area of the seance and they see that Pontius was performing an auto-seance as well. The Farseer then helps reveal what Pontius saw which made the scene make more sense.
  • Perilous Old Fool: The best example is Lord Inquisitor Phlebas Alessandro Rorken - he banishes an Eldritch Abomination by charging it with a holy flamethrower and yelling prayers.
  • The Pirates Who Don't Do Anything: While he can hardly be accused of "not doing anything," Eisenhorn is The Ordo Xenos Inquisitor Who Doesn't Deal With Aliens Very Often. (The Ordos Xenos and its Inquisitors are supposed to deal exclusively with alien threats.) This is mostly because he keeps getting distracted by heretics, daemonhosts, other Inquisitors, and his own past decisions come back to bite him in the ass. Is there a variant for "The Pirates Who Don't Do Anything Related to Piracy"?
    • Though his allegiance to the Ordo Xenos might explain why he was so sensitive to Ravenor's remarks about the virtues of the Eldar.
  • Psychic-Assisted Suicide: An Alpha-plus psyker compels Eisenhorn to shoot himself in the head. Eisenhorn fails to resist the command, and only outside intervention prevents him from carrying it out.
  • Punny Name: Prophaniti.
  • Ragtag Bunch of Misfits: Eisenhorn's retinue. Included in their number: a gunslinging pilot, an aging scholar who's literally addicted to knowledge, an ex-cop, an anti-psychic prostitute, and a flamboyant starship captain. And that's just the first novel.
  • Really 700 Years Old: Cherubael qualifies, as he is thousands of years old.
  • Right Hand Versus Left Hand: Eisenhorn regularly finds himself pitted against other Inquisitors with ideological stances either more Puritan or Radical than his own. He states outright that his possession of the Malus Codicium would prompt half the Inquisition to try and kill him for having it and the other half would do the same in the hopes that they could get their hands on it.
  • Scars Are Forever: The torture that Eisenhorn went through in Xenos produced permanent and noticeable nerve damage in his face. Suffice to say, Gregor cannot smile anymore.
    • Also an example of Cursed with Awesome - it comes in handy when Eisenhorn is trying to conceal his emotions from non-psykers, since he has the ultimate poker-face.
  • Shout-Out: Eisenhorn lost his virginity to a maid in his boarding school, at the age of sixteen. Like a certain other notable intelligence agent...
  • Sinister Geometry: The Lith is a sentient geode shaped like a perfect decahedron. It enslaves the population of Cinchare Minehead with its psychic powers, compelling them to worship it and merging many of them into a giant flesh monster, and it seeks to spread its influence across the stars.
  • The Smart Guy: Deconstructed with Aemos' meme-virus, which leads him to memorize the whole of the Malus Codicium.
  • Soul Jar: The "Pontius" turns out to be one for an Imperial nobleman-cum-dangerous chaos cultist named Pontius Glaw, whose mind and possibly soul now exist in a small sphere of black crystal. When a mechanical body is built for him, the Pontius crystal is revealed to be its core, located in the machine's head.
  • Spinoff: Interrogator Ravenor, a supporting character in the Eisenhorn books who was pretty much developed from a namedrop in the Gaunt's Ghosts series, later became the protagonist of his own novel series. Eisenhorn itself is a spinoff of the Inquisitor Gaiden Game to Warhammer 40,000, and the first novel was released concurrently with the game itself.
  • Spy Speak: Glossia is an entire language of spy speak developed by Eisenhorn and his acolytes. It's even consistent enough that a reader can work out most of what they're saying from context.
  • Star-Crossed Lovers: Eisenhorn and Bequin, who fall for each other, but their inherent natures prevent them from ever pursuing it; a psyker simply cannot stand an Untouchable getting near them.
    Eisenhorn: I was a psyker, she an Untouchable. That way pain and madness lay.
  • Stating the Simple Solution: In Mallus, when Eisenhorn is at his wits end trying to figure out how his enemies could be operating on Cadia, Tobias Maxmilla surprises him by sneaking onto the fortress-world with no-one the wiser. When questioned, Tobias smugly reveals that he just borrowed Eisenhorn's credentials, since nobody would dare interfere with the Inquisition. This leads Eisenhorn to realize that the suspicious flights he had written off as the business of Inquisitor Neve were actually the villains, using her stolen credentials to mask their activities.
  • Strange-Syntax Speaker: The first book gave us the alien Saruthi, who did this when they spoke English Gothic. Ironically, that was probably the least strange thing about them.
  • Summon Bigger Fish: In Hereticus, Eisenhorn is forced to summon Cherubael after all his other attempts to defeat a Chaos Battle Titan have failed. Cherubael destroys the Titan with one attack, and then sets its vengeful sights upon Eisenhorn.
  • Take Up My Sword: Voke invokes this in Xenos, asking Eisenhorn to take over his protégé's training if he actually does die. He doesn't, at least not then.
  • Talk to the Fist: At the end of Xenos, Konrad Molitor corners Eisenhorn on the top of a collapsing Saruthi edifice and demands that he hand over the primer for the Necroteuch. Eisenhorn responds by shooting Molitor dead.
  • Tampering with Food and Drink: Eisenhorn was poisoned this way three days before the start of Malleus. The first chapter has him launch a desperate raid on the poisoner’s hideout in search of an antidote, starving and dehydrated because consuming anything would cause the poison to immediately kill him.
  • Taught by Experience:
    • In preparation for the final assault in Xenos, Eisenhorn is given his pick of elite Guard regiments. He chooses to stick with the comparatively basic Gudrun Rifles because they've experienced what being in a Saruthi tetrascape is like before, which is something no amount of simulation can adequately convey.
    • After Cherubael defies him a few times to his great cost, Eisenhorn has the latest form triple-bound, reducing its power but making it much more docile.
  • Tears of Fear: A typical result from human characters when confronted with some of the more terrifying aspects of Chaos such as tainted Chaos Space Marine armour or the tomb on Ghul.
  • Tell Me About My Father: Medea Bentacore asks this of Eisenhorn, in regards to her father Midas Bentacore (who was Eisenhorn's team pilot in the first book until he died between books).
  • Theme Naming: The three novels are titled after the major Ordos of the Inquisition.
  • Time Abyss: In Hereticus, the Chaos Titan Cruor Vult has existed since the Dark Age of Technology, making it tens of thousands of years old. Eisenhorn gets a glimpse of its memories when he enters its mindscape, and is almost driven mad by the experience.
  • Tome of Eldritch Lore: The Necroteuch and Malus Codicium.
  • To the Pain: In Xenos, Eisenhorn.
  • Traintop Battle: In Hereticus, Eisenhorn duels a mercenary swordsman on top of a luxury train during a blizzard. The train isn’t moving at the time, but the icy roof makes up for it in terms of precariousness.
  • True Companions: By Hereticus, Eisenhorn considers Aemos, Bequin, and Fischig to be his dearest friends and his support network, with Aemos being a source of wisdom and knowledge, Bequin being his emotional rudder, and Fischig acting as his conscience. This makes it all the more tragic when he loses all three of them.
  • Vengeance Feels Empty: In Hereticus, after the death of the man who killed her father, Medea realizes that her desire for revenge was really displaced desire to have known her father. (She asks Eisenhorn to tell her about her father).
  • Villainous Breakdown: Pontius Glaw has a fatal one when Eisenhorn burns the Malus Codicium. Cherubael has an understated one when Gregor binds him again in the second book.
  • We Hardly Knew Ye:
    • Xenos: Lores Vibben dies shortly into the first chapter.
    • Malleus introduces several new members of Eisenhorn’s retinue in the first chapter, including Mescher Qus, Arianrhod Esw Sweydr, and Gonvax. All three of them are dead by chapter two.
  • Well-Intentioned Extremist: A vital theme throughout the series, and a central part of the last two books. As an Inquisitor, Eisenhorn is this by definition. He starts out with more emphasis on the "Well Intentioned" side and ends up with more on the "Extremist."
    • And then an even further confusion is heaped on that judgment when you understand that the people declaring him to be a heretic are overwhelmingly Knight Templars, with periodic sprinkling of Lawful Stupid.
  • Wicked Cultured: Pontius Glaw was an Imperial nobleman in life, and displays both wit and a learned mind when bantering with Eisenhorn (though his reference pools are a few centuries outdated).
  • Worthy Opponent: Between Eisenhorn and Glaw, to the point where Eisenhorn muses that - in a very different universe - they would probably have been very close friends.
  • Would Not Shoot a Good Guy Averted in Malleus where Eisenhorn is forced to kill Arbites and Inquisitors who believe him to be a heretic.
  • Wrecked Weapon: Actually vital in stopping Malleus's Big Bad.
  • You Wouldn't Shoot Me: In Hereticus, a thoroughly disillusioned Fischig holds Eisenhorn at gunpoint and demands that he stop moving. Eisenhorn dismisses the threat, confident that his old friend won’t shoot him... and is promptly shot in the kneecaps.