History Fanfic / TheRoboutianHeresy

''The Roboutian Heresy'' describes an alternate universe for ''TabletopGame/Warhammer40000'', where Roboute Guilliman was the one to lead nine Space Marine Legions in rebellion against the Emperor. The Legions which were loyal in canon are traitor in this universe, and vice-versa.

* TheAce: Many of the finest of the Astartes Legion and the Imperium in canon remain the same in the RH-Verse, with only their alliegiances changed.
** The Sons of Horus are an interesting case of this AND the ButtMonkey: They were acclaimed as the greatest of the Space Marines during the Great Crusade and is still considered so in the RH-verse. In contrast to the Ultramarines in canon however, ever since Horus' untimely demise their grand glories are often overshadowed by misfortune, sometimes rivalling the Lamenters in canon, with many failures and setbacks tainting even their greatest victories as well as countless grudges and oaths of vengeance against their archenemies which remain unresolved well over ten thousand years.

** Unlike their canon counterparts, the Night Lords of are justice-obsessed mystics who see justice as the ultimate end, and terror is just a means to attain it. The canon Night Lords saw terror as an end in itself.

Inspired by ''FanFic/TheDornianHeresy'' by Aurelius Rex, ''The Roboutian Heresy'' describes an alternate universe for ''TabletopGame/{{Warhammer 40000}}'', where Roboute Guilliman was the one to lead nine Space Marine Legions in rebellion against the Emperor. The Legions which were loyal in canon are traitor in this universe, and vice-versa.

Because this is a fanfiction of ''TabletopGame/{{Warhammer 40000}}'', please consult that page for tropes pertaining to the original universe of which this fanfic is set.

** Unlike their canon counterparts, the Night Lords of ''The Roboutian Heresy'' are justice-obsessed mystics who see justice as the ultimate end, and terror is just a means to attain it. The canon Night Lords saw terror as an end in itself.

** Inquisitor Fidus Kryptman (best known for exterminating planets to starve tyranids, and luring them to fight the orks) run into conflict with Death Guard over said practice, which escalated to the point that Inquisition decided that it's easier to throw him under the bus than make peace between them. He was eventually tracked down and killed, but not before causing much more destruction.

** Subverted with, of all people, [[spoiler:Daemon Primarch Sanguinius]] regarding the above, [[spoiler:after the reveal that [[CrazySane he is not as crazy as he pretends to be]]]]. The Chaos Gods, by their very natures as monstrously-selfish reality-cancers, were unable to predict and thus prepare for the Emperor's final Hail Mary against Chaos. However, [[spoiler: Daemon Primarch Sanguinious]] who before his downfall was [[spoiler:one of the closest Primarchs to the Emperor]], possessed both the memories and just enough Humanity left in him to deduce the Emperor might pull something as selfless as his Hail Mary, and thus prepared accordingly [[spoiler:through his avatar/alias of the Sanguinor]] to take advantage of it while the Imperium is still reeling. If true, it would explain why and how [[spoiler:Sanguinius/Sanguinor]] was able to [[spoiler:engineer the Angel War to strike at the Sol system almost the moment the Emperor died from his sacrifice]], potentially giving [[spoiler:Slaanesh the best shot at destroying the Imperium at its heart or at the very least cripple it before they can rally and take advantage of the Emperor's sacrifice against them]].

* TheExtremistWasRight: [[spoiler:Thiel made a pact with an entity (likely Malal) and spent thousands of years in the Ruinstorm turning the Ultramarines upon themselves; one of the quotations in the Battle of Macragge reveals his actions have [[ScrewDestiny changed fate]], making it so that it's possible for Roboute to ''lose'' the final battle.]]

* {{Foreshadowing}}: All over the place.

*** On Colchis, Lorgar grew up as part of a family in Colchis that directly suffered under the Covenant's oppression. Instead of becoming a religious zealot, when he grew up he became the Covenant's worst enemy and the most ardent supporter of the Imperial Truth, as well one of the most anti-Chaos Primarchs in the entire Imperium.

* BloodBrothers: In this universe, Angron ranked brotherhood first, discipline second, and fighting prowess third on the list of things he wanted the World Eaters to value.

* IncorruptiblePurePureness: Cited at the start of the fic as to why it exists. Discounting successor Chapters, there is only ''one'' recorded canonical instance of an Ultramarine falling to Chaos, and that was from demonic possession that was eventually fought off. ''FanFic/TheDornianHeresy'' likewise softballs the Ultramarines' betrayal by simply having them adopt a neutral, independent state.

** Downplayed with Ferrus Manus. While he was very much a Jerkass compared to the other Primarchs during the Great Crusade, he didn't willingly embrace Chaos and instead had Nurglite corruption forced upon him due to the collaboration of Nurgle and Slaanesh. It also helps that, unlike canon Fulgrim's murder of canon Ferrus, RH Ferrus and the Iron Hands ''didn't'' deliberately betray and lure the RH Emperor's Children into the Dark Eldar trap when they called for help against the Diasporex.

* CloningBlues: Obviously when Fabius Bile is around. [[spoiler: He is a bunch of clones, in fact.]]

%%* ThirteenIsUnlucky: Invoked by Magnus in a saying regarding the Ultramarines.

* ThirteenIsUnlucky: Invoked by Magnus in a saying regarding the Ultramarines.

It can be found [[https://www.fanfiction.net/s/10578370/1/ here]] and [[https://forums.spacebattles.com/threads/the-roboutian-heresy-a-warhammer-40k-alternate-universe.440554/ here]]

* BreakTheHaughty: The Emperor's Children go through a legion wide example when they all end up in the Webway fighting the Dark Eldar. Fulgrim came out of it no longer the pretty one.

* AuthorityEqualsAsskicking: How many Chaos warbands work: in particular, Ultramarines warbands practice a twisted sort of meritocracy.

*** Horus is implied to have a slightly more positive view on his father as a result of how their first meeting went. The Emperor was also less blunt and a much nicer person than in Canon, so he was able to put his son's concerns and questions at ease when he withdrew from the Great Crusade and made Horus the Warmaster. Horus was also helped by his more compassionate and diplomatic brothers in shouldering his duties as Warmaster so he was not overwhelmed by the burdens of his position, and was encouraged to soften his approach to make things easier, leaving him less doubtful of himself and less obsessed with his achievements. Also, as they were no PoorCommunicationKills between them, the Sons of Horus did not exterminate the Interex after both sides were able to clear up any confusion between them with the latter helping the former prevent Horus from being corrupted ([[spoiler:Sadly, the Interex are still killed off by an unknown force after the Sons of Horus were forced to leave their new allies when the Roboutian Heresy began]]). Additionally the now-loyal Erebus, rather than orchestrating Horus' downfall, alerts him Horus to the Chaos corruption on the planet, prompting them to exterminate the Davinite tribes.

*** Horus is implied to have a slightly more positive view on his father as a result of how their first meeting went. The Emperor was also less blunt and a much nicer person than in Canon, so he was able to put his son's concerns and questions at ease when he withdrew from the Great Crusade and made Horus the Warmaster. Horus was also helped by his more compassionate and diplomatic brothers in shouldering his duties as Warmaster so he was not overwhelmed by the burdens of his position, and was encouraged to soften his approach to make things easier, leaving him less doubtful of himself and less obsessed with his achievements. Also, as they were no PoorCommunicationKills between them, the Sons of Horus did not exterminate the Interex after both sides were able to clear up any confusion between them with the latter helping the former prevent Horus from being corrupted ([[spoiler:Sadly, the Interex are still killed off by an unknown force after the Sons of Horus were forced to leave their new allies when the Roboutian Heresy began]]).

* OrcusOnHisThrone: Played with. All of the Daemon Primarchs have a reason they're sitting around in the Eye of Terror instead of going out to destroy the Imperium. Lion'El Johnson suffers from a debilitating WoundThatWillNotHeal until all the loyalist Fallen Angels are dead, and so he sits on the throne until that happens. Rogal Dorn is busy searching for Sigismund, who betrayed him and broke his Legion (and made Dorn so angry that he became a Daemon Prince). Sanguinius is ''completely insane'' and spends most of his time in a self-imposed (and imperfect) LotusEaterMachine. Ferrus Manus actually isn't fully attuned to Nurgle due to his metal hands, and is waiting for them to flake off. Vulkan is implied to be worried about being KilledOffForReal. It is also implied Vulkan intends to become a full blown Chaos God, which he can safely do from his throne. Finally, Corax is too busy torturing the people who made his life a living hell. The moment they're DeaderThanDead, he gets off the throne.

** Dorn's is rage: lots and lots of rage. Meanwhile, Lion El'Jonson suffered from paranoia (due to the whispers of Kalros Fateweaver). Sanguinius was willing to do anything to save his Space Marines, and Ferrus Manus couldn't stand weakness, including his own. Finally, Leman Russ couldn't trust psychic powers ([[{{Hypocrite}} despite making use of them]]) and Roboute ultimately made an impulsive decision when a demon brought up his adopted family.

*** [[spoiler:Be'lakor]] stirred up war in Macragge that led to the deaths of the two people Guilliman considered as parental figures, and years later Guilliman furiously pursued [[spoiler:Be'lakor]] into the Warp and exposed himself to the corruption of the Ruinous Powers.

** Several Traitor Marines are, if you ask them, trying to save humanity. Everyone else is... skeptical, to say the least.

** ZigZagged with Corax. While it is unquestionable that he suffered at lot at Kiavahr, it also prevented him from having any form of cultural upbringing. Because of that, he never developed neither conscience nor empathy. At all. And his morals can be described as "ends justify the means". With all horrible consequences. [[spoiler: Reinforced when it's revealed that Yellow King is the dark side of the Emperor, meaning that all Corax's misadventures is connected to the very being he hates and serves.]]

** The Doom Of Eisenhorn: Reply to Yellow King, by Pontius Glaw [[spoiler: "You... are my [[EnemyWithout Emperor]]"]].