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


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.

Alpharius wore at least four sets of Armour before the Heresy he had discarded when they showed signs to identify him. To disguise Alpharius Omegon further members of the Alpha Legion would drink a substance mixed with the Primarch’s blood that seems to temporarily turn them into him. The disguise is so convincing that even the Legion’s own Apothecaries are fooled by it, and those who undertake the process are even given some of their Primarch’s memories.



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.

Despite their close bond and describing themselves as two halves of the same soul, Omegon’s loyalties may not lie with his brothers (or vice-versa). During the Horus Heresy Omegon took suspicious steps against his brother. This included sending troops on a suicide mission to destroy a Pylon array preventing the White Scars learning about Horus’ betrayal without his brothers apparent knowledge. Afterwards, an Alpha Legion fleet that may have been under Omegon’s command did not follow Horus’ orders to join with the White Scars, but instead seemingly provoked them into hostilities after blockading them long enough for Jaghatai Khan to receive a message from Rogal Dorn warning of Horus’ treachery. As the Alpha Legion are known for schemes within schemes, the true nature of these acts may never be known. However, Alpharius and Omegon may not see completely eye to eye as the former is more accepting of civilian deaths than the latter.



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.


Alpharius in battle-garb

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.

Later in the Heresy, Alpharius dispatched forces to attempt and block the White Scars from leaving the Chondax Campaign and joining loyalist forces. The White Scars were alerted to the Heresy after Omegon initiated a mission to destroyed a jamming array. Despite a fierce battle with the White Scars these ships may not have been armed, further compounding the true nature of Alpharius and/or Omegon. Alpharius went on to corner the Space Wolves under Leman Russ himself, nearly destroying them and dueling Russ disguised as one of his own Lernaean bodyguards. Victory seemed certain for Alpharius until he was forced to withdrawal after the loyalists received Dark Angels reinforcements.


Alpharius (or Omegon) battle Rogal Dorn during the Heresy.


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.

Wargear & Equipment

Typical of the Alpha Legion’s nature, Alpharius and Omegon utilized completely non-standard and inconsistent wargear and the Primarch himself did not typically engage in open combat. He often preferred using Cameleoline-lined cloaks and armour that partially cloaked the wearer. However Alpharius and Omegon were observed utilizing reptilian-style Power Armour known as The Pythian Scales.  One of his stranger reported weapons was the Xenos artifact known as the Pale Spear. Alpharius Omegon was also seen with Power Swords and Plasma Guns in combat situations.

Curiously, Omegon possesses a suit of grey power armour that he keeps hidden from even his brother Alpharius

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?

  • Wayne Molina

    Got to say I prefer the old original fluff where they were basically trying to be the best because they were the last Legion created and as a result their Pride got the better of them. I know they have said this is the fluff as it was always intended but I never liked the whole I am Spartacus maybe we’re loyal maybe we’re not hahaha I’ll never tell you kind of thing

    • plasticvicar

      II found the old fluff to be limited if not forgettable, in fact there was so little old Alpha Legion fluff that Relic even chose Alpha Legion as the antagonists for 2004’s Dawn of War because there was almost no chance of there being any canon conflict.

      I personally find the new fluff to be fantastic, no other legion treats its non-astartes personnel as actual members instead of slaves, servants or cannon fodder and Alpha Legion’s focus on the espionage and subterfuge of the Heresy far from the epic battles is a great change of pace from the typical spess muhreens war porn of other books.

      As for which side they are on? Thats easy, they chose neither.

      • Wayne Molina

        Mmm to each their own. The new fluff has been the one thing that always made me ignore Alpha Legion despite the cool looking color scheme (also hail hydra), because it seemed silly cartoon villain type of stuff.

  • Dennis J. Pechavar

    My favorite Legion and Primarch.

  • jmaximum

    wait, Alpha Legion treats the human servants as….not slaves? (Can’t say equals, I guess)>
    Also, above: Omegon has a spare grey power armor suit? Part of Malcador’s grey knights/inquisition? Seriously? When did that come around that Omegon is secretly working for Malcador?

    • Morgrim

      Grey power armour doesn’t necessarily mean working for the Inquisition, it just means no heraldry to indicate what is going on. And yeah, the Alpha Legion considers valuable members to be valuable members, and treats them appropriately. If you’re marked as one of them, you’re one of them. Abet a squishier member that might need protection.

      They’re also the only Legion known for occasionally fighting without wearing power armour at all, for the occasions where they don’t want witnesses to know they’re Space Marines. (Even though it is noted that they’re giants compared to baseline humans, the idea of Space Marines NOT being in armour is so foreign they’re assumed to be some secret special unit of IG or Inquisition and avoided.)

      • jmaximum

        Huh. Cool!
        I need to read more alpha legion fluff!!
        There is a cool fan-fic of the 40K endtimes that features the Alphas heavily, but don’t know if I can post links to other forums here

  • MVBrandt

    SPOILER and major retcon in this weekend’s book.

    Snapepharius killed by Dumbledorn (no shens, Omegon becomes Alph).