Lexicanum keeps a page called Traitors of the Loyalist Legions. Its category has thirteen entries. The matching page for loyalists inside the traitor Legions runs to whole formations: an Iron Warriors grand battalion, a Thousand Sons fellowship, the Emperor’s Children’s 34th Millennial, and everyone Horus tried to purge on Isstvan III. So when someone on r/Warhammer40k asked this week whether the Dark Angels were really the only loyalist Legion to have part of their strength fall in the Horus Heresy, the honest answer is no. The file on loyalist-legion traitors is just much thinner than you’d expect.
Thirteen entries, and only five Legions on the list. I’d have guessed hundreds.
The thread got the usual replies. Somebody said every Legion had traitors. Somebody else said Marines follow their primarch and that’s the end of it. Both are half right. What I wanted to know was which Legions actually lost people, how many, and what they did about it afterwards, and on the last of those the Dark Angels come out alone.
Which loyalist Legions had traitors
The White Scars are the one real parallel to Caliban, and I’ve written about their mutiny before so I’ll keep this short. In Chris Wraight’s Scars, Hasik Noyan-Khan, one of the Khan’s original Chogorian companions and commander of a twenty-brotherhood horde, tried to seize the fleet over Prospero and hand it to Horus. Torghun Khan and Hibou Khan were with him. The warrior lodges had been working on the Terran-born marines for years (Torghun had originally been meant for the Luna Wolves, which tells you something). Shiban Khan’s Brotherhood of the Storm broke the plot and the conspirators surrendered. Forge World’s Book Eight: Malevolence adds a brotherhood under Nayaga Khan, the Brotherhood of the Great Eye, that went over to Horus openly with the 905th Expeditionary Fleet and was later wiped out by loyalist Scars.
Malevolence calls the Prospero rising “brief.” You’ll see people online saying half the Legion turned. Nothing I read supports that.
The Raven Guard are messier. People reach for the Raptors first, Corax’s rushed gene-crafted recruits from Deliverance Lost. Alpha Legion infiltrators poisoned the gene-tech and turned most of them into monsters, and they stayed loyal anyway. Horribly loyal, in fact. The Corax stories have a Raptor commander, Navar Hef, killing a Space Wolves pack under Arvan Woundweaver because he was scared they’d report what the Raptors had become. The actual Raven Guard traitors are smaller and sadder. Captain Rovac handed the 44th Armoured Company to the enemy after the Dropsite Massacre and fought for them for the rest of the war, according to the Beta-Garmon campaign book. Alastor Rushal, once captain of the 89th, ended up running with Sevatar’s Night Lords in Prince of Crows. Book Six: Retribution mentions a pro-Horus Blackshield band of Raven Guard that killed twenty million civilians around the gas giants of Euros, and that one’s a single line in Retribution with no names attached.
The Iron Hands had Clan Ayreas’s Order Secundii, which carried a Mechanicum envoy to Mars and fought the loyalist garrison at Magma City during the Schism. That comes from the Legions Imperialis Rise of the Dark Mechanicum supplement, which is about the last place I’d have thought to look. The Ultramarines had Consul-Chaplain Ankarion of the 547th Company, turned to Nurgle by the Word Bearers in the tunnels under Calth. He helped destroy his own company and died in the same blast as his captain, according to a Warhammer Community PDF from 2022.
And the Space Wolves had the Dark Wolves. I’ll come back to them.
I went looking for my own Legion
So, Imperial Fists. My army. About three thousand points of yellow, some of it even finished. Imperial Fists traitors? None I can find. Blood Angels, none named either, and no Salamanders. Which, fine, good, loyal boys. But also I went looking specifically because of a model, and I’m a bit annoyed about it still.
Back in 2014, maybe early 2015, I built a traitor Imperial Fist. Tactical marine body, a Chaos Marine backpack with the spiky exhausts, and the aquila scraped off his chest with a hobby knife, which I did badly enough that it looked less like heresy and more like he’d fallen down some stairs. The plan was a lone renegade for a narrative game. I painted him Averland Sunset with a Nuln Oil wash over everything, and the wash pooled in the gouges and made the whole thing look like a banana that had been left in a bag. A mate at my local store picked him up, turned him over, and asked which Imperial Fist traitor he was meant to be. I said I’d look it up. That was over a decade ago, which is longer than my kid’s been alive, and the answer’s still nobody. He’s in a bits box now with a Rhino door glued to his foot for reasons I can’t reconstruct.
The rules have caught up with my banana man even if the lore hasn’t. Liber Astartes gives every loyalist Legion traitor-only options, so you can field a Blood Angels force that sided with Horus. So GW has given permission for these people to exist. I haven’t found one of them written up in a Black Book.
Why the Fallen are different
It took me a while to see what the other cases have in common. Every one of them got dealt with inside the war, by the Legion, usually in front of the primarch.
The White Scars’ ending is the clearest. The Khan put the mutiny down himself, and the survivors he didn’t execute he formed into the Sagyar Mazan, penitent suicide squads sent wherever the dying was worst. The Path of Heaven has 132 of them left after four years. At Catallus they held Mortarion aboard the abandoned Swordstorm while it was set to overload, and Mortarion killed Torghun personally. That’s a closed file. The Legion knows exactly who betrayed it, where each of them ended up, and it paid the account off in public. Rovac and Rushal are war crimes on a list. Ankarion went up with his captain’s melta bomb.
Caliban happened after the war. Horus was already dead. According to Visions of Heresy, Luther had spent decades stranded on the homeworld with a garrison the Lion had sent back to train recruits, and he’d turned “generations of new recruits” against a primarch who then came home to be fired on from orbit. Then the warp opened, the Lion vanished, and the Fallen didn’t die. White Dwarf #446’s Index Astartes feature says they were scattered through time and space, and that the surviving Masters decided nothing about Caliban would be revealed to the wider Imperium. That decision is where the Inner Circle comes from, and the whole ten-thousand-year secret, and Cypher, and the hooded Interrogator-Chaplains, and basically everything that makes the Dark Angels weird.
The Dark Angels lost theirs later, with no primarch to judge them, and the traitors kept walking around, like an ex who still has a key to your flat. White Dwarf #464 has some of them running whole worlds in the Imperium Nihilus now.
I’m honestly not sure the numbers even favour the Dark Angels. GW has never put a figure on the Fallen. Luther’s garrison was big, but “sizeable contingent” in Visions of Heresy could mean anything from a few thousand to a Legion’s worth of recruits, and I’d guess the Hasik plot involved at least as many bodies on paper. If it turned out the White Scars lost more, I wouldn’t be shocked…
Actually, hang on. I’m arguing against my own point here and I should let it stand for a second. You could say the Space Wolves have a Fallen of their own and nobody talks about it. The Beta-Garmon book has Skyrar’s Dark Wolves, a Sons of Horus captain who merged his command with part of the Space Wolves’ 6th Great Company that had declared for Horus. They massacred Neo Cadiz and went pirate. Book Four: Conquest mentions rumours that a whole Great Company turned. And the Dark Wolves are still around in M41: Imperial Armour 13 has them invading Imperial space in late M38 alongside a warlord called Tallomin, and when the Space Wolves turned up to stop it, that only fed “the unvoiced suspicions” about where the Dark Wolves came from.
But it’s a sidebar in a Forge World book, and it has been for twenty-odd years. The Space Wolves’ codexes don’t organise the Chapter around it. No Wolf Priest has a secret inner order dedicated to catching them. Nobody’s founded a successor Chapter whose whole job is chasing the Dark Wolves the way the Angels of Redemption chase the Fallen. So I end up about where I started, just less smug about it, and still wondering whether the Wolves simply never had a Luther to put a face on it.
The Blackshield problem
One thing that nags at me: the grey zone. Visions of Heresy describes the Blackshields, the warbands who blacked out their heraldry and declared for nobody, and says they were “as likely to come from traitor as they were loyalist formations.” Some came back to one side or the other and fought with honour. Some vanished and reappeared centuries later as renegades.
Which means every loyalist Legion probably had legionaries who walked off during the Heresy without anyone recording where they went. They don’t make Lexicanum’s thirteen because nobody knows their names. The Alpha Legion fought Blackshields in the Pale Stars that were made up of exactly these people, and I don’t remember GW ever breaking down where most Blackshields started out.
I don’t know how you’d count them. I’m not sure GW does either.
White Dwarf #464 adds one detail about the Fallen that I didn’t know until this week. Some of them walked out of Caliban with the knowledge to make new Space Marines, and a handful have the means to do it. So a Fallen warband can replace its losses. The Dark Wolves presumably could too, if they’ve survived since M38, and whatever became of Rovac’s tank crews didn’t need gene-seed at all.
My traitor Imperial Fist is still in the bits box. I might strip him and paint him black as a Blackshield, since nobody can check.
