''Titanicus'' is a standalone novel by Creator/DanAbnett, set in the ''TabletopGame/{{Warhammer 40000}}'' universe. When the vital forge world of Orestes comes under attack by a legion of Chaos Titans, the planet is forced to appeal for help. Titan Legio Invicta, although fresh from combat and in desperate need of refit and repair, responds, committing its own force of war engines to the battle. As the god-machines stride to war, the world trembles, for the devastation they unleash could destroy the very world they have pledged to save.

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!!As part of ''TabletopGame/{{Warhammer 40000}}'', the novel involves a large number of the tropes on that page, as well as employing literary and narrative tropes of its own:
* AnyoneCanDie: It's a Dan Abnett novel.
* ArtificialLimbs: The members of the Adeptus Mechanicus are augmented to varying degrees.
* BarBrawl: A drunken Stefan kills a man from [[Literature/GauntsGhosts Tanith]] after he indirectly badmouths Cally.
* BoisterousBruiser: The skitarii, the military arm of the Mechanicus, are described as being boastful, loud, and flamboyantly dressed (the Invicta skitarii favor feather-crested helms), in contrast to the dour, disciplined, and subdued Imperial Guard stationed on Orestes.
* BookBurning: [[spoiler:Imanual]] burns any sequestered book that comes his way that might threaten the Imperium. It's how the conspirators suss out that he'll never side with them, as ''they'' are the ones leaking the books.
* CivilWar: The revelation about the God-Emperor and the Omnissiah threatens to split both the Imperium and the Mechanicum, as well as fracture the Mechanicum itself. Civil war is only narrowly averted by the novel's end.
* CoversAlwaysLie: There are no Space Marines in this book.
** The Black Library France cover averts it, showing a Warlord titan instead.
* CurbStompBattle: The Orestes Pride Armor corps is wiped out by the Chaos Titans, due to the latter's superior maneuverability and firepower.
* CyberneticsEatYourSoul: Princeps Maximus Pietor Gearheart is worried about losing his personality to the machine spirit in his Titan, ''Invictus Antagonistes''. He strives to know his crew personally and even makes it a point to try to engage them in smalltalk, so he can hold on to his humanity.
* DangerousForbiddenTechnique: Linking the control of multiple Titans to one princeps is forbidden, as interacting with multiple machine spirits at the same time runs the high risk of driving the princeps insane, as well as being potentially vulnerable to {{cracker}}s. [[spoiler: When the Dark Mechanicus unleashes its Imperator-class Titan in the penultimate battle, Princeps Kung orders all of the Invicta Titans to link their control to his own Titan. They do so under protest but it allows Kung to target all of their weapons at one spot on the enemy Imperator, which causes its shields to completely short out, allowing the Imperium forces to tear it to pieces. Fortunately, Kung is able to do this quickly enough to avoid damaging his sanity.]]
* DoomedByCanon: The conspirators of Orestes plan on divorcing Mars and Terra (ignoring their enemies' plea that it would be disastrous for both). Considering what we know about the future of [[TabletopGame/{{Warhammer 40000}} WH40K]], they obviously can't succeed.
* EnsignNewbie: Guido Prinzhorn, a princeps from Legio Tempestus, is assigned to take the place of the princeps of the Legio Invicta Titan ''Dominatus Victrix'', whose entire crew save Moderati Zane Tarses was killed when Invicta was battling the Eldar in their last mission. Unfortunately, Prinzhorn has never seen actual combat. [[spoiler: After some difficulty getting along with Tarses, it turns out he manages to acquit himself well enough when the shit hits the fan.]]
* GuiltRiddenAccomplice: [[spoiler: Egan, Feist's boss, ascribes to the belief in a separate and distinct Omnissiah, but he [[NotWhatISignedOnFor does not want to be party to murder]] and is distraught when Tolemy kills Imanual, and when Feist is slated to be killed as well. When Tolemy accidentally implies that he manipulated the data that caused the schism, he kills Tolemy to prevent him from killing Enhort (who was willing to call off the whole plot and reconcile with Invicta and the Imperium, since the reason for the schism was now in doubt), but then turns his bolt pistol on himself.]]
* HeroicSacrifice: [[spoiler: Varco's entire crew of survivors perishes in order to bring down the Chaos tower]]. Meanwhile, [[spoiler: Imanual sacrifices his life own life in order to help Feist and Kalien escape the conspirators]].
* HeKnowsTooMuch: Feist, Kalien, and [[spoiler: Imanual]]. Only the latter gets offed, however.
* HumongousMecha: It's Imperial Titans verses Chaos Titans on a scale rarely seen since the HorusHeresy.
* {{Irony}}: [[spoiler: Cally and Stefan are both afraid she won't make it home from the war. Cally survives on the battlefield against all odds. Stefan gets himself gunned down by a hometown policeman.]]
* JustBetweenYouAndMe: Feist earnestly requests that the conspirators explain their plan to him before they kill him, and then they do so. [[spoiler: Feist records the entire conversation.]]
* MadnessMantra: "The magnos organos's name was Kercher."
* MachineWorship: While all the members of the Adeptus Mechanicus engage in this practice, ''Titanicus'' sees the debate on the theological relationship between God-Emperor and the Omnissiah reach a breaking point. The members on Orestes generally see the Omnissiah as a separate being, while the members of Legio Invicta see them both as the same. Also, at several points, a few people on both sides of the ideological divide roundaboutly argue -- to avoid open heresy -- that it doesn't matter if the God-Emperor isn't the Omnissiah; Mars and Terra can't endure independent of one another, and attempting to divorce them will just invite extinction for both.
* ManipulativeBastard: [[spoiler: Tolemy, master of the archives, is the one that comes up with the plot to initiate the schism between the Mechanicus and the Imperium. Turns out he's doing this purely for personal gain, as the plan would result in him becoming Adept Seniorus of the forge, a position he felt was unfairly denied him.]]
* MaybeMagicMaybeMundane: Varco has an Omnissiah medallion that was originally attached to the armor of his tank, ''Queen Bitch'', and after ''Queen Bitch'' is destroyed by a Chaos Titan, the medallion mysteriously appears in his pocket, and for the rest of the story it seems to give him some incredibly good luck.
* NiceJobFixingItVillain: The surprise attack conducted by the second armada of Chaos engines helps to avert a civil war that could possibly have destroyed the Imperium and driven humanity to extinction. To be fair, they weren't exactly in a position to know an EnemyCivilWar was about to break out.
* TakeOurWordForIt: The reader is not told ''how'' the God-Emperor and the Omnissiah are proved to be completely unrelated, only that the evidence is pretty much bulletproof.
* UnstoppableRage: Tarses snaps and kills the magos organos who tells him his wounded princeps died during transit. He feels immense regret about it once he's cooled down, and only avoids summary execution because Legio Invicta needs him, the sole surviving member of his Engine's original crew, to ease in the newbie replacements.
* UnwittingPawn:
** Kalien is this to the conspirators.
** [[spoiler: Tolemy expects Enhort to be one for him]], but that lethally backfires.
* WellIntentionedExtremist: [[spoiler: Enhort]] genuinely believes he's the doing the right thing by proving the Omnissiah and the God-Emperor are not one and the same, as opposed to [[spoiler: Tolemy]] who's just making a power grab.
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