40K Lore: Alpharius, Lord of the Alpha legion


Today we delve into the byzantine web of lies and deceit that is the Primarch Alpharius, master of the XXth Legion.

“Truth is so precious that she should always be attended by a bodyguard of lies.” ~Proverb, Old Albia, M.2

via our sister site: Lexicanum

Alpharius is an enigmatic figure within the history of the Legiones Astartes. No definitive record of his appearance and activities exist. There are claims that Alpha Legion Marines assumed his name and identity during wars and even council meetings with other Legions and Imperial officials, that Alpharius was somehow able to duplicate himself, and that he had a twin. Reports of his physical appearance seem to widely differ.

Secrets and Lies 

It should be noted that the Alpha Legion‘s trademark secrecy extends to records of their Primarch. Little recorded information on his background exists, and almost all of what is currently known by the Imperium comes from the information provided by Inquisitor Kravin of the Ordo Malleus. Inquisitor Kravin was subsequently believed to have been tainted by the Alpha Legion and his current whereabouts are unknown. Hence, much of the Imperial data concerning the Primarch could be considered suspect, and indeed there are some who believe the whole Kravin affair was an Alpha Legion plot to plant misinformation in the Imperial records.

Alpahrius wore at least four sets of Armour before the Heresy he had discarded when they showed sings to identify him.


The greatest secret about the Alpha Legion Primarch is apparently told to none outside the Legion, and has always been thus. For, unlike any of the other Primarchs, Alpharius has an identical twin: Omegon. It is unknown if the Emperor designed this, or was ever even aware of it. Alpharius and Omegon are both the Primarch of the Legion, although ‘Alpharius’ is the public face and appears as the more senior of the two. Though as both are identical it is possible for them to switch roles and have ‘Omegon’ play the public role. At least once ‘Omegon’ appared before the small court of Horus instead of Alpharius, that had appared the last time to the court. They have been described as “one soul in two bodies” and collectively have been referred to as simply “Alpharius Omegon”.

While the Astartes of the Alpha Legion, once at least, made an attempt to all look alike, both Alpharius and Omegon were still somewhat distinctive. Taller than the rest of the Legion, slightly copper-skinned, bald and possessed of a heavy brow, they somewhat resembled their brother, Horus. Unlike him, Alpharius and Omegon had piercing eyes that seemed to glitter, appearing to shift colour from a cold arctic blue to a shimmering green. The overall impression was one of nobility and intelligence. One way to tell the two apart was when Omegon was performing as commander of Effrit Stealth Squad; large portions of his power armour and gear were painted black and otherwise darkened. The armour worn by Alpharius was not particularly different from that of an ordinary Alpha Legionnaire.


Typical of the Alpha Legion’s own nature, conflicting tales of how Alpharius was rediscovered by the Imperium exist. Many of the tales have been proven lies, while many more still remain unproven or unknown.

What is known is that Alpharius was the last of the lost sons of the Emperor to be found, some scant decades before the end of the Great Crusade. While most other Primarchs, aside from Rogal Dorn, were found on the worlds they had been cast upon, Alpharius apparently came upon Horus’ Fleet in an unnamed system.

Using a ragtag fleet of primitive one and two-man fighters he cleverly put the advance ship of the Luna Wolves‘ fleet in a precarious position, which necessitated the intervention of Horus himself. Arriving on his endangered cruiser, he soon learned that a small team of boarders was making its way towards the bridge. The cruiser was at high alert as the five boarders burst onto the bridge. Quickly four of them were dispatched by Bolt Pistol shots from Horus. The fifth one, who towered even over the Luna Wolves’ marines dodged Horus’ fifth shot, and continued to advance regardless of the gunfire. At the last instant, Alpharius stopped his assault, as both he and Horus realised the situation. Horus laughed, for he had found his last brother.

It is said that instead of immediately sending him to Terra to meet the Emperor, Horus kept Alpharius with him for some months. The two formed a strong bond, with Alpharius and his ragtag alliance quickly embracing the Imperium. Both brothers were greatly impressed with each other, although Alpharius refused to reveal his homeworld, denying that each world in the system that the brothers brought into compliance was his point of origin. Eventually, Alpharius had to journey to meet his father, the Emperor. Their meeting was, as were all times when the Emperor found one of his lost sons, surrounded with much celebration. However, since the Great Crusade was in full swing, little time was spent in idle rejoicing and Alpharius was quickly given command of the XX Legion, created just a few decades before. Renamed the Alpha Legion, they followed their Primarch on Crusade.

Alpharius quickly developed a unique approach to Astartes operations, focusing on the philosophies of initiative and flexibility, as well as extensive use of subterfuge and non-Astartes specialist operatives. This multitudinous, almost unstructured approach rankled with Roboute Guilliman, Primarch of the Ultramarines, leading him to question Alpharius’ approach to fighting. A violent discussion erupted between the two which was closed when Guilliman pointed to his own Legion’s record, something that Alpharius could never hope to achieve, since his Alpha Legion was almost two hundred years younger than the Ultramarines. They parted company acrimoniously, Alpharius believing Guilliman hated him. He resolved to ignore the Ultramarine Primarch from then on.

However, the criticism stuck; Alpharius began to push his Legion even further. More and more were the situations where he would take the more difficult course of action to force his Space Marines to grow. Plans were more complex, more subtle, while at the same time relying on more and more factors to achieve victory. Training was more intense and new strategies and approaches were constantly developed, as Alpharius sought to prove the worth of both his Legion and his martial philosophy.

The Heresy

It has long been supposed that since Alpharius was only familiar with one other Primarch, Horus, it was self-explanatory why he chose the side he did at the outset of the Heresy. Indeed, the very plan at Isstvan V where Horus struck his first blow against his fellow Legions by destroying most of the Iron HandsRaven Guard and Salamanders Legions in a massive ambush, was very reminiscent of plans that Alpharius had created in the past. However, it is possible that there is another reason for Alpharius leading his Legion to the side of the traitors, a secret known only inside the Legion. Two years before the beginning of the Heresy, Alpharius Omegon was apparently contacted by members of a Xenos organisation called the Cabal, who brought to him visions of the impending civil war within the Imperium, and expanded knowledge of the nature and designs of Chaos. It is believed that the Cabal convinced Alpharius that the only way to permanently defeat Chaos was to ensure that Horus was victorious. It is perhaps for this reason that Alpharius Omegon, secretly true to the Imperium and loyal to the Emperor, may have chosen to join the heretics. Further during the Heresy, the Cabal sought to lead Alpharius Omegon behaviour in order to make Horus victory easier. One of such actions was the operation against the Raven Guard with the intent of preventing Corax to rebuild his legion after the blow struck on Isstvan V. Some Alpha Legion marines were infiltrated, under the direction of Omegon, into Raven Guard thanks to Alpha Legion apothecaries grafting the facial traits of some dead Raven Guards over the face of their own legionaries. Once they discovered, through their infiltrators, that the original genome of the Primarchs was in the hands of Corax, Omegon acted in order to recover the secret knowledge so thet the Alpha Legion could be expanded in future times. With the help of renegade Mechanicum magos Unithrax, the Alpha Legion tainted the original genome recovered from the laboratories of The Emperor on Terra. This was accomplished introducing a virus-vectored mutagen based on daemonic blood making the successive Raven Guard implantations result in operational but deeply-mutated Astartes exhibiting scales, horns, fangs, tails, overgrown muscles and similar features. Meanwhile, Omegon bound to his service, both a renegade Mechanicus faction and some representatives of the ancient and noble guilds of Kiavahr. He pushed them to open rebellion against the Raven Guard and, in the chaos resulting from the battle, he personally recovered all the data stored in Corax’s laboratories as well as the tainted original Primarch genome. In the aftermath, Alpharius was obliged to give the obtained data to Horus who handed them to Fabius Bile for deeeper research. What Bile did not know, was that the data was practically useless or incomplete at best. Of course, the Alpha Legion kept for itself the complete data as well as the corrupted genome. The Plan of Alpharius had always been to use the Data to raise the Alpha Legion over all other legions, loyalists and traitors alike. After this action, Omegon cast the Cabal representitve onboard his ship into the void stating that the legion would fulfill its engagement on its own, without external interference or control.


During the Heresy Alpharius appeared more interested in proving his own Legion’s worth by fighting, at every chance he got, the best of the Loyalist legions. Thus, even after Horus was cast down and the Heresy over, the Alpha Legion kept on fighting, moving more and more towards the galactic east, towards the Ultramarines. It was on the world known as Eskrador that Alpharius and Roboute Guilliman would meet for the last time.

Believing that Guilliman would adopt his standard Codex deployment procedures, Alpharius was surprised by the Ultramarines, as a splinter force including their Primarch made a quick strike at the Alpha Legion’s headquarters. Both Primarchs met in combat and Alpharius was killed. Believing the combat over, for what legion could ever survive the loss of their Primarch in battle, the Ultramarines were taken by surprise by the remaining elements of the Alpha Legion, when they struck back a day later. After a week of constant fighting and heavy losses, the Ultramarines strike force managed to reunite with their main elements, and quickly evacuated the planet. Even though they had lost their Primarch, the Alpha Legion had soundly beaten the Ultramarines, who proceeded to bombard their foes’ position from outer space. It should be noted, however, that Alpharius’s death is still considered suspect even by the Ultramarines, and he may still be at large. On the other hand, it is possible that ‘Alpharius’ did indeed die and ‘Omegon’ took sole command of the Legion. It is also possible that it was ‘Omegon’ who was ‘killed’ by Guilliman after taking the place of ‘Alpharius’. Whatever the truth, the Primarch of the Alpha Legion has not been seen since.

Learn More of the Alpha Legion


So do you think the Alpha Legion are really traitors, or are they pulling off a 10,000 year “inside job” on Chaos?

  • helline9

    Alpha legion is on Alpha legions side

  • Secundum Ave

    What the Ultramarines don’t know, is that it was Gulliman who was killed and the current Gulliman is Alpharius. =D

    • Jake Nolan

      I wouldn’t doubt it with GW’s hokey logic.

    • Deathmage

      See that cultist, the Dark Vengeance one. That’s Alpharius, as are all of those skeletons on the fantasy table next to you. And that Stormraven? Definitely Alpharius

      • But all are actually deathleaper

        • Carnage

          in the guise of Sly Marbo

          • Syratogo

            Who is actually alpharius

          • Dennis J. Pechavar

            Dressed up as Alpharius.

          • petrow84

            And all were according to the plans of CREEEEEEEED!…

            Who, in turn, was a puppet of Tzeentch…

            Who served the allmighty will… of the Squats’ Venerable Ancients.

  • Damistar

    I asked Dan Abnett at Adepticon a couple years back if the Alpha Legion were loyal or on the side of Chaos. He replied “If they weren’t then they are now.” Considering the Alpha Legion, that’s an excellent answer.

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    • Captyn Bob

      Of course he does have a hinted alpha legion loyalist in his ‘Pariah’ novel set in the 40k period…

      • Damistar

        Abnett’s reply neither confirmed nor denied either possibility. That’s why I thought it was fitting.

      • Syratogo

        Actually as that guy is working for a renegade inquisitor… it’s hard to determine loyalties.

  • msgellar

    Never understood how the emperor would not know he created twin primarchs.

    • amaximus167

      And they do not want you to understand. Confusion is their ally.

    • Malevengion

      I believe they became twins while in the warp. (Sort of Sanguinius’ wings).

      • Michael Ray

        In the book “The First Heretic”, there are two of them in the birth/incubation pod before chaos even gets them into the warp.

        • Malevengion

          That’s odd, I just read the book and didn’t catch that. (There was more attention paid to whether they should do the Imperium a favor and slay the two fallen primarchs).

          • Michael Ray

            I remember the comment being made about “too many arms and legs to belong to just one person” in one of the pods.

          • Syratogo

            I think that’s in False Gods when Horus has the vision on Davin, of being in the big E’s labs.

      • Michael Ray

        In the book “The First Heretic”, there are two of them in the birth/incubation pod before chaos even gets them into the warp.

    • Red_Five_Standing_By

      Their cells split while in the warp.

      • petrow84

        I like that explanation above with the First Heretic one – maybe some sort of siamese twins, separated by the warp.
        The Emperor could definitely have put an ultrasonographic device to good use…

        • Red_Five_Standing_By

          Weren’t the Primacrchs grown in artificial incubators?

          He should have invested in transparent glass…

  • So when it comes time to settle the bill do ya think they are all still Alpharius?

  • Malevengion

    It would be fun, when Forgeworld gets around to them, if Alpharius deployed hidden in a unit of regular marines until he was revealed to the horror of whatever unit they we engaged with. According to fluff he was almost indistinguishable from the marines in his legion (at least when his helmet was on).

    • Knight_of_Infinite_Resignation

      they have done the rule, and that is indeed how he deploys.

      • Malevengion

        Fantastic! I only have the first Forgeworld HH tome so far so I didn’t know. Thanks!

        • Syratogo

          Yeah good shout that’s more or less exactly it. I think you’re obliged to shout: SURPRISE! PRIMARCH!

    • Damien Coté

      That’s the part I don’t understand; aren’t primarchs significantly larger than their marines? It even says so in the article here… so how does he hide?

      • Dennis J. Pechavar

        He is said to be larger but not as large as their brother primarchs. Some space marines were as large as they were so it isn’t as big a deal.

      • Malevengion

        I’m an identical twin myself and my brother and I were on the small side growing up. I would imagine that it’s possible that Alpharius Omegon didn’t receive the best in nutrition growing up and didn’t achieve the gigantic stature of their brothers. The world they ended up on is unknown but, given the rest of the fluff about the primarchs, it was probably a death world of some sort. Just my guess.

  • Koszka

    Stupid Olsen twin 30k shenanigans.

    • Dustin Dean

      Haven’t read any of the Alpha Legion novels?

      • Koszka

        Spoiler alert: Alpharius and Omegon get two unlikely strangers to fall in love and become a happy family.


        • Dustin Dean

          You know more about the Olsen twins than I do…

  • Dennis J. Pechavar

    I still hold out that the “Alpharius” that was killed was a new one made with the genome. Would be amazing if they made a couple dozen Alpha Legion primarchs…

  • WarlordEXE

    I don’t see how the emperor didn’t know alpharius had a twin. During the word bearers novel (sorry the title escapes me) argel tal noted that one of the primarch incubation tanks looked to have two people in it. Now he probably didn’t understand the significance, but if I recall correctly Lorgar had the same experience. I’m sure he would have noticed this just like how he was able to notice the change in Fulgrim.

    As to whether the Emperor knew that both Alpharius and Omegon were recovered that could be debatable, but given his psychic prowess surely he would have noticed a difference when the twins were switching roles.

    Also, technically the ‘traitor’ legions were fighting for the empire as well. Just one with their father deposed and replaced by Horus. The real question is whether or not the Alpha Legion except the chaos gods, and thats something only Alpharius knows. Or maybe the other alpharius, or the alpharius down the street, or the………

    • Wraith

      Not necessarily. Remember the line ‘one soul in two bodies’, if that were indeed true then they may – at that point – have only exuded one psychic signature.