Alternate Heresy

The Horus Heresy is one of the biggest events in the Warhammer 40,000 story. Naturally, people like dreaming up alternate scenarios. Page still being expanded.

In-Universe Alternate Heresy

In Lorgar's visions with the daemon Ingethel the Ascended he gets shown alternate futures in which he stabs Sanguinius and then gets executed by Horus "for his sins", and another one in which he gets taken out by Curze and Russ working together "for defying the Anathema." He also gets instructed by Kairos Fateweaver to avoid at any costs a duel to the death with Corax lest he get his shit pushed in. These are explained as "possible futures" which did not come to pass; in each case it would seem that Lorgar is still the First Heretic, but the arrangement of loyal primarchs is different. Notably, in the actual events that ended up playing out, someone who is not Chaos switched the Khan and Fulgrim's fates.

There's also the consideration of the short story "The Board is Set", which details a massive game that the Emps and Malcador had been playing, revealing that the Heresy War was, to some extent, a calculated outcome. The problem was that the meddling of those four assholes had meant that His actions were reactionary, but far from the worst outcome given the circumstances. This was also where big E revealed his final gambit, one that would most certainly screw over the Sigilite.

Deviations

Deviations (name pending) are generally similar to the original canon but with some changes. In the vein of "What If...?" Marvel Comics. A majority replace the arc-traitor with another primarch

The Dornian Heresy

The Dornian Heresy was the 40K web forum Bolter & Chainsword's project to switch the allegiances of the various Primarchs during the Heresy, and explore what would have happened to the Legions under their command if they had fallen or not.

Unlike the following scenarios, which were largely thought exercises in random threads on /tg/, this was a full project, with accompanying Index Astartes articles and quite a bit of fluff, which can still be found quite easily.

Essentially, during the incident on Davin, Magnus the Red actually arrives to visit and exorcise the infection on Horus instead of relying on Erebus' rituals. While successful at both saving the warmaster's life and preventing him from becoming corrupted, it did leave him out of commission. Following their temper tantrum, the Chaos Gods decided that the next best choice was Rogal Dorn, who had been going on overdrive with his pet pain glove.

In the end, the Space Wolves fell to Khorne as part of their rabid psyker-hate. The Blood Angels fell to Nurgle in an event almost identical to the canon Death Guard, plus the bit where they practically owed their lives to Nurgle like Magnus canonically did to Tzeentch and now forced to recruit mutants to their cause. The White Scars fell to Slaanesh because Khan got drunk off his vanity and ego while sending his loyal sons to die on Chogoris. The Raven Guard fell to Tzeentch, Corax himself being fed haunting visions of the future by Tzeentch. The Salamanders fell to Malal out of total disillusionment with the Imperium, and Rogal Dorn himself became the arch-traitor, with his Imperial Fists supporting Chaos Undivided (renaming themselves the Black Legion after the failure of the Heresy). The Ultramarines did not fall to Chaos, but instead became Reasonable Marines; they seceded from the Imperium alongside much of the Ultima Segmentum, and now exemplify progress while fighting off the Tau. The Iron Hands seem to have gotten mixed up with the Necrons, while the Fallen Angels won out over the loyalist Dark Angels, with Luther triumphant.

On the Imperial side, the Word Bearers became the Ecclesiarchy (with no Kor Phaeron to twist it all to heresy - he proved incompatible with the gene-implants), the Iron Warriors remained siege masters, the Sons of Horus became the crusading Black Templars (after almost identically disowning Horus' foolishness which led to the Emperor being mortally wounded), the Emperor's Children remained exemplary perfectionists (except for Fabius Bile, but he's dead now... except not), the Thousand Sons became blind psychic warriors (see: Grey Knights), the Death Guard became the core of the Inquisition, the World Eaters became serious instead of angry, the Night Lords remained loyal Scary Marines without going over the edge, and the Alpha Legion were just as sneaky and just as anti-Ultramarine, but still loyal (apparently The Cabal wasn't that convincing in the Dornian Heresy).

How the Space Marines are organized is also flipped, as the legions falling to Chaos occurred because of them being separated by all sorts of circumstances, so Abaddon (who takes over as leader of the Imperium after the Emperor's battle with Dorn) organized the legions into a few giant armies (by Space Marine standards).

It's pretty awesome...except that, as most alternate heresies are wont to, it all amounts to some absurd amounts of marine-wank. Perhaps the most particular is the Reign of Blood, where the Sisters of Battle never existed, because they were wiped out by the Word Bearers when they were still the Brides of the Emperor, and Goge Vandire (who was now the new Chapter Master following Lorgar becoming a martyr post-heresy) wasn't overthrown by some simple preacher, but by a novice marine named Sebastian Thor. To be fair, can you really imagine the Word Bearers not recruiting him? Meanwhile, all of the xenos factions are left to mere footnotes or mentions (just as Games Workshop intended) and the impact this has had on the Imperium at large is left to interpretation.

The Imperial Heresy

In the Imperial Heresy, the God-Emperor of Mankind decided "if you can't beat 'em, join 'em" and sided with the Gods of Chaos.

The Eldar Gambit

In the Eldar Gambit, Eldrad meets the Emprah the day before the final assault on the Vengeful Spirit, offering assistance in exchange for closer Eldar - Human cooperation later.

The basis of the pact is that instead of taking the mortal blow that Horus throws at him on accident, he does it deliberately, and uses the energy of his own death to attack the Chaos Gods directly, specifically Slaanesh. He steals the stomach of Slaanesh and incorporates it into himself, so now all Eldar souls will go directly to him when they die, keeping them safe from the depredations of Chaos.

The thread was mostly speculation on how a united Imperium of Man and Eldar Empire would work together... and it's actually pretty awesome. Ollanius Pius being revered by guardsmen as an Avatar of Khaine(or Khaine revered as his avatar) and killing Horus right after Horus defeated the Emperor (albeit he was weakened from fighting the Emperor he's a motherfucking Primarch jointly possessed by all Four of the Chaos Gods, there is no "albeit" about it), Space Marines with soulstones to keep the forces of Chaos away from loyal marines, a fractured Adeptus Mechanicus (with four factions - Traitor, Loyal, Machine God fanatics and Fundamentalist (doesn't use Eldar tech that is now more freely available)), and more.

The Roboutian Heresy

The true heresy has begun: Papa Smurf takes the place of Horus and fucks over the Imperium. Much shedding of blood, sweat and tears ensues, with generous helpings of manliness on the side. It's pretty awesome.

Inspired by the above mentioned Dornian Heresy, circumstances happen that lead to the Primarchs who turned traitor in canon to stay loyal and the loyalists to turn traitor. For this Heresy's loyalists this ranges from having a small point that causes a major divergent in their lives, like Konrad and Angron, to having completely different lives like Lorgar. The Traitors all at a certain point have a moment that led them towards Chaos, some better done than others, even the fic's writer admits El'Jonhson's could have been done better, but the rest bring much tragedy and sorrow, though a bit less so with Vulkan (his moment of divergence is absolutely horrifying, but it isn't as sad because of how awful Vulkan and the Salamanders are in this timeline). However, even Vulkan and the Salamander's horrors pale in comparison to that of Corvus Corax and the Raven Guard.

Of the traitors, Vulkan was raised- then killed by, a female fire drake, causing him to realize his immortality early on and gain a god-complex. This wish came true when he, hating the 4 chaos gods but believing SO HARD in his own superiority, actually turned himself into the chaos god of greed and pride! I.e., a giant chaos version of Smaug. Rogal Dorn fell to Khorne due to a massive ork fleet almost destroying the Inquit System and destroying the Phalanx, leading to him never using his magic pain glove to temper his anger. Lion El'Jonson spent too long in the warp-tainted wilds of Caliban and became corrupted by Tzeentch. Sanguinius grew up with an even greater fear of mutants and deviation, causing enough doubts and fear that, when Slaanesh came knocking, he gave himself and his legion up willingly. They then turned into full-on horny space-vampires who get off on drinking blood. For being the archtraitor, Rowboat himself had a pretty lazy bog-standard "hometown and parents were destroyed and became more brutal because of it" backstory as well as being manipulated by Be'lakor, meaning he's a once great hero who turned evil through a combination of losing loved ones and Be'lakor playing him like a fiddle. Jaghatai grew up with chaos worshippers and Russ lost his pet wolves, Geri and Freki, while executing the Lost legions. Ferrus became an utter social darwinist and got infected by Nurgle when he tried to blow up a daemon world. Then there's Corvus Corax, who was in the care of the mad scientists of Kiavahr and, seeing his immense scientific potential, proceeded to slice him up, poison him, disembowl him, tear off and reattach his limbs, and countless other horrific tortures in the name of 'science.' It only gets worse, as he himself became a mad scientist, created horrific astartes clones called Spawn Marines, and became an avatar of a previously unknown chaos god of emptiness and the void (Malal?)

For the loyalists, Konrad had a loving mother who helped develop his moral compass into less of a Punisher and more like Batman. When Horus first met his father, their meeting was more cordial and he saw that Big E was just a tired, old man who wanted the best for humanity, under all the glitz and glamour. Magnus fought a titanic psychneuein on Prospero, learning to use his muscles instead of his powers when the creature was immune. When Tzeentch offered to save his sons from the Flesh Change, Magnus said no and basically cured it himself. Now much more cautious, he sent Ahriman to help Horus during the crusade, allowing them to heal Horus and thus the Warmaster never fell. Peturabo, as new Preatorian of Terra, performed a far better job than Dorn did in the Horus Heresy, making a stellar defense for Terra and even constructing huge rings of planetary fortresses around the Eye of Terror and Ruinstorm to keep chaos caged up after the Heresy, called the Iron Cages. By killing his Witchlord foster father, Mortarion learned how to get shit done as he took up the role as Big E's executioner, killing/banishing both Jaghatai and Vulkan singlehandedly before his demise in two separate moments of Awesome. Lorgar and Angron had loving parents and used their psychic charisma to lead revolts against their cruel planetary governments, with Angron never getting the Butcher's Nails, and Lorgar slaying Kor Phaeron when he saw the horrors the cults of chaos were capable of. Fulgrim having a few librarians with him meant he never took up the daemon sword of Slaanesh... buuuut the Eldar didn't know that, so Eldrad convinced the Dark Eldar to kidnap him and subjected him to decades of disgustingly extreme torture so Slaanesh couldn't have him, on the pretense of a faulty prophecy. Thanks Eldrad! Finally, Alpharius Omegon had their pragmatic and ruthless ways tempered by Konrad, so they turned out to be one of the single most valuable chapters of astartes the Imperium has. The Alpha Legion also became buddies with the Rogue Traders, which is pretty cool.

Notably, Fabius Bile is still evil, but a little less so here given that here he has a reason for being evil that his main version lacks, and even he is horrified by the sheer awfulness of the corrupted Raven Guard.

Can be read here (also contains sidestories and word of god).

Can also be read here (see threadmarks) for reactions from the primarchs and the Emperor himself.

The Leonine Heresy

What it says on the label: The-Leonine-Heresy

The First is taking his turn at ruining the galaxy. This is one of the more unique Alternate Heresies in that the primarchs are not swapped 1 for 1, but it is a mix of loyalists and traitors on each side. Mix that with an emphasis on grimdarkness and enough slaughter to impress even Khorne, and you get a story as colossal as the Imperial Palace. Inspired by the Roboutian Heresy and the Shape of the Nightmare to Come/Age of Dusk fanfics.

Like with the Roboutian Heresy, differing circumstances have resulted in drastic personality changes for the various primarchs. For the loyalists, Konrad Curze and Lorgar both got a stern talking to from the Emperor, causing them to remain loyal. Their roster includes Leman Russ (aka Odin), Konrad Curze (blind-folded avatar of justice who sacrifices himself fighting the Archtraitor), Ferrus Manus (WHO COULD FORGET HIM?), Mortarion (pissed beyond belief that he has to be a loyalist), Horus Lupercal (doesn't do too well in the Iron Cages), Lorgar Aurelian (the Saint who arrives too late to save the day), Vulkan (Praetorian of Terra), Corvus Corax (first victim of the Heresy who gets his head pulped like Oberyn Martell), and Alpharius and Omegon (who realized a group of xenos probably aren't the most trustworthy).

For the traitors, we have Lion El'Jonson (Archtraitor as a result of the Rangda and a puppetmaster worthy of Tzeentch, Fulgrim (Landed on Chogoris, depressed beyond belief because he's the chosen of Nurgle with a Blight-crippled legion), Perturabo (Allied with Vashtorr, Master of the Eye of Terror, and Breaker of Fists and Luna Wolves alike), Jaghatai Khan (lands on Chemos, gets teamkilled by Guilliman), Rogal Dorn (hates Perturabo, hates the Emperor for not making him Praetorian, simple as), Sanguinius (the Red Angel, Chosen of Khorne for once, has the Sanguinor for a stand), Angron (kills Corax, only to be team-killed by a berserk Sanguinius shortly after, his sons have renounced him to serve Malal/Unicron/something), Roboute Guilliman (Chosen of Slaanesh, everything he says is a reference, most often toward David Bowie), and Magnus the Red (Still Tzeentch, but utterly insane; his sons are now wild mutants instead of dusty robots).

Can be read here.

Can also be read here, but with more comments and responses from the author.

Warhammer High

Technically an Alternate Heresy, as in there was no Heresy at all and the Emperor decided Malcador's ideas were not stupid after all and made 19 female Primarch children to give the Primarchs some responsibility Post-Great Crusade, something to live for, a chance for family, and because he really wanted Grandkids.

It's a bit.....weird.

Imperium Ascendant

The Most Fuck-Ass Awesome Timeline: The Legion of the Damned are sent back in time by the Throne-Emperor to stop the scattering of the Primarchs by Argel Tal. After they succeed, the Emperor of the past looks upon the future that is the galaxy of 40K and vows to ensure that such a nightmare will not come to pass as the Ascendant Imperium strikes out against the darkness. In short, The Emperor learns where the Canon timeline will lead, and decides to take corrective measures.

The original author got depressed by the chaotic corruption of GW and didn't feel like continuing and handed the project over to another writer. First part here, and the second here.

Nobledark Imperium

Probably one of the more divergent Alternate Heresies out there. Like Warhammer High technically an Alternate Heresy despite there not being a heresy at all. Nobledark is as much a retelling of the 40k universe with intentional twists as it is a straight alternate timeline, sort of like Hektor Heresy or Imperium Asunder, though in general all parties receive a buff to reason and common sense, as you would expect from a universe that is nobledark as opposed to grimdark.

Instead of earning the ever-lasting hatred of the Chaos gods by doing {{REDACTED}} that led to the creation of the primarchs (who in this timeline are the Emperor's greatest, though otherwise similar to canon in name and deed), in this timeline the Emperor plotted with Eldrad and agreed to a last alliance of elves and men a team-up between the nascent Imperium and the Eldar to free Isha from Nurgle’s garden to weaken the Chaos Gods in exchange for access to the Webway and anti-Chaos lore.

The Imperium and Eldar expect to go their separate ways after the Raid on Nurgle's Mansion, until Chaos decides to supercharge the War of the Beast in order to show those mortals what happens when you steal fire from the gods. The Chaos Gods don't manage to turn any primarch (though they get really close with Horus), the Emperor having told the primarchs what Chaos what it is and why it is important to not touch it beforehand. Humanity and Eldar are forced into an alliance once again, resulting in an Aesir-Vanir-esque political marriage between the Emperor and Isha. Although things are bad with the biggest green tide the Imperium has ever seen and Luther convincing the majority of Dark Angels to go traitor, they only gets worse when the true mortal catspaws are revealed.

Because that buff to competence and common sense? Chaos gets it too. And in a spectacular display of long-term planning, instead of consuming ALL of the pleasure cult-worshipping eldar in the Eye upon their birth, Slaanesh only consumed MOST of them. So now in addition to daemons, orks, and traitors, you have an entire army of insane, Chaos-worshipping fair folk who just declared holy war on the Imperium and their heretic kin.

And it all kind of spirals out from there.

Can also be found at Nobledark Imperium Drafts, the other main page for the project.

Shattered Imperium

The canon legions fracture into more than two factions. Imperial Fists, Raven Guard, Salamanders, and Blood Angels remain loyal to Emps. Sons of Horus, Word Bearers, Alpha Legion, and White Scars go Chaos. Thousand Sons, Iron Hands, and Emperor's Children go transhumanist. Death Guard, World Eaters, Night Lords, and Iron Warriors go egalitarian. And finally the Ultramarines, Dark Angels, and Space Wolves go independent of everyone.

MidHammer

The setting that tries to find a balance between the grim darkness of the original Warhammer and BrightHammer.

The Vulkanite Heresy

A less-grim, less-dark, but still solidly grimdark timeline. Vulkan can't stomach the purges of the Lost Primarchs and goes renegade. Eventually this makes him easy prey for Lorgar and Tzeentch, and Chaos gets a Heresy War. Featuring a mix of canon loyalists and traitors in the heretic faction, more renegades and semi-traitors (Oh, Hi Malal), and a decompressed timeline of events. Indexes Astartes are viewable on Ao3 and reddit, with some older material about the primarchs also on reddit. That will eventually be superseded by Biographica Primagenesis entries for them, and some Xenos entries, particularly for changes wreaked on the Eldar, will be inbound, but that will all be after the Index Astartes are finished.

The Sanguinary Schism

A fan heresy with Sanguinus as the traitor warmaster. No wiki yet cause the admin is tech illiterate https://www.facebook.com/SanguinarySchism/

There is also another version of the Sanguinary Heresy, here

If the Emperor Watched If the Emperor had a Text-to-Speech Device

Due to mysterious warp nonsense, the canon timeline just after the triumph of Ullanor when all the Primarchs minus Alpharius Omegon (who arrive later) were together receives the TTS videos and other Lexicanum, 40k Wiki, Codex and 1d4chan information in the form of videos and text files. The Emperor and the Primarchs (minus the twins who as stated arrive later and the lost two who were already purged) watch them to great hilarity. The main thread is on Spacebattles in this thread, while side stories and reactions to fanfiction, homebrews and other files like the wiki articles and the alternate heresies are on this thread. The Extras thread got locked by mods and the main thread is locked due to hiatus so things have moved to SufficientVelocity in this thread. The previous thread has been abandoned. A continuation has been made here. Main story is written by Praetor98 and sidestories of the main thread and all of the extras thread is made by readers.

The Cyclopean Heresy

What if Magnus the Red was the Arch-Traitor? The arrangement of Loyalist and Traitor Primarchs are completely different, with Mortarion of the Death Guard becoming Warmaster of the Imperium during the Heresy, replacing Horus who was stripped of that title when he went traitor.

Can be read here.

Everqueen

Isha manages to avoid being captured by Nurgle and being devoured by Slaanesh, and ends up incarnating to Terra during the Unification Wars. Big E finds her and decides to imprison her and make her his servant as she would very useful to his plans. Author has stated that no, the two will not have a romance between them.

Can be read here.

Renegades

Shortly before the Canon heresy would have begun, the Emperor decides that he wants to be a god. He allies with the Chaos Gods and ropes in several Primarchs into his plan to make the Imperium worship him as a god. This does not go down well with Horus and Magnus, who start seeing dark changes in the Imperium and the way it is run. They create a coalition of legions to oppose the Imperial legions, and the civil war begins.

Renegades deals with the buildup to the civil war, and the civil war itself. It continues to this day. A good read, and a rather interesting one.

Can be read on AO3 here.

The Fulgrimian Heresy

An alternate heresy where it is Fulgrim who is the Arch-Traitor. Arrangement of Loyalist and Traitor Primarchs are different, with more primarchs remaining loyal to the Emperor than joining Fulgrim and the Traitors. It's an excellent read.

Can be read Link here

Alternate Heresy Community Project

This is an alternate heresy with an interesting premise. Instead of the Primarchs landing where they normally do, they land on different planets, which causes them and their legions to have different personalities and areas of specialization. This causes a different heresy. The thread can be found here

The Alpharian Heresy

Another alternate heresy, where the planets the Primarchs land on are switched up. Alpharian of the Primus Legion falls to Chaos and causes a heresy that splits the Imperium. It consists of three reddit posts linking to documents. The Alpharian Heresy, the Primarchs , The Alpharian Heresy, Corruption of the Primarchs , First Phase of the War

This Won't End Well(Isekai)

A sorta kinda 40k Isekai, with a unique new 2nd Legion. Later chapters are much less Isekai, and more pure Warhammer AU. Found here. Has some actual tabletop rules written by the author, probably mainly as a way of contextualizing the 2nd Legion within 30k.

Replacements

Replacements are where the story is generally the same up to a point (usually the scattering), but the key difference is a completely new roster of Primarchs and their legions.

The Hektor Heresy, AKA the /tg/ Heresy

/tg/ Creates an Alternate Universe of 40K Astartes legions and discusses how the heresy would play out between them. Since then it has spiralled into a near-total overhaul of the 40K universe as a whole. Although there are variations in quality and completion, the project feature original art and write-ups for the new primarchs and their legions, original regiments of the Imperial Army, a new take on the Squat, and other warhammerania. For those interested in the origins of the project: Archived /tg/ threads can be found at http://archive.moe/tg/thread/34414189/ (Initial Legion creation) and http://suptg.thisisnotatrueending.com/archive/34432982/ (Alternate Heresy thread)

Imperium Asunder, AKA the /tg/ Heresy II: Electric Boogaloo

Yet another alternate Heresy with all-new Primarchs, only one where the Emperor is outright killed and Chaos consumes half the Galaxy, while the Loyalists fracture into a number of warring empires on the Eastern Fringe.

Warmasters Triumvirate, AKA the /tg/ Heresy III: Reloaded

A third alternate Heresy with new Primarchs. After the Emperor is incapacitated relatively early on, he leaves three of his sons in charge of the Great Crusade, the Warmasters Triumvirate. When more power is given to the Council of Terra and regular humans, tensions begin to rise. This one has 21 Space Marine legions, pitted against each other in a three way Brotherwar between the Imperial Loyalists, Chaos Traitors and Confederated Seperatists.

Brotherhood of the Lost

The Icarion Insurrection = First AU created by Brotherhood of the Lost, started on Bolter & Chainsword, with the starting question being: "What if the canon legions were replaced by lost legion projects?" A three-way war between the loyalists, insurrectionists, and the smaller suzerainty, lasting for decades. This AU has since been discontinued and the writers split into the following two new AU's; The Five Ruins and The Broken Throne

Sub-forum can be found here.

Wiki can be found here.

The Five Ruins

The newest project from the Brotherhood of the Lost combining old talent with new blood and legions, the Five Ruins project is set in an ever-escalating conflict caused by the disappearance of the Emperor on His way to Ullanor. 18 new legions and Primarchs who are left to pick up the pieces as the galaxy trembles in anticipation of the horrors to come. A compromise situation is reached, a High Regent appointed, but in the process fundamental differences between certain Primarchs or parts of the Imperium develop that are exploited by the forces of Chaos. The Imperium slowly devolves into a husk of its former self as legions fall to Chaos or lead a breakaway Separatist movement, the Galaxy divided and the fate of Humanity uncertain.

Sub-forum can be found here.

Wiki can be found here.

The Broken Throne

Founded after a certain difference of opinion in the Brotherhood of the Lost project led to the demise of the Icarion Insurrection and a bunch of the creators walked out and took their Legions with them. Warmaster Yucahu of the Void Eagles has been assassinated, the Emperor has disappeared amidst chaos at the heart of the Palace, and the new Lord Regent Kozja of the Warbringers must to pick up the pieces whilst faced with an increasingly violent opposition from other Primarchs. Meanwhile, Ixiplatlan of the Eagle Warriors pulls strings from behind the scenes to incite civil war and spread the reach of the Primordial Annhilator.

Once everybody's figured out which side of this Machiavellian mess they're actually on, the Loyalists must launch an attempt to retake Terra and disrupt Ixipatian's ritual. In the aftermath of the climactic battle warp storms ravage the galaxy, and the Imperium fragments into hundreds of factions striving for their survival.

Sub-forum can be found here

Wiki can be found here.

Legions Reborn

New legions and Primarchs to lead them, not dissimiliar to the Hektor Heresy above.

Wiki can be found here.

A final side note

The most likely places to find Alternate Heresies, besides /tg/, are the usual fanfic sites (fanfiction.net and AO3), and Spacebattles.

Gallery

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  Loyalist Legions of the Roboutian Heresy

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  Traitor Legions of the Roboutian Heresy

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  Loyalists of the Fulgrimian Heresy during the Siege of Terra

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  Theoretical Daemon Primarch version of Leman Russ.

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