Event · M31
Battle of Eskrador
The Battle of Eskrador was a post-Heresy engagement of the Great Scouring in which Roboute Guilliman and the Ultramarines struck the Alpha Legion on the world of Eskrador. Imperial tradition holds that a primarch answering to the name Alpharius was killed there in personal combat with Guilliman after an Ultramarines elite detachment made a surprise assault on the Alpha Legion headquarters, departing from the Codex deployment pattern the XX Legion had expected. The Alpha Legion did not break. Remaining forces turned on the Ultramarines detachment, inflicted near-total casualties before it could rejoin the main body, and drove the Ultramarines from the planet in the fighting that followed. The Ultramarines later bombarded the Alpha Legion position from orbit. Even among the XIII the death is treated as suspect; the Legion may have continued under other commanders, and the primarch may have survived. Which twin died on Eskrador, if either did, is not settled. The earlier account of Alpharius’s death at Pluto at the hands of Rogal Dorn complicates the Eskrador tradition: some within the Alpha Legion hold that it was Omegon who fell to Guilliman, while others maintain that Omegon lived. No subsequent public appearance of either twin is securely attested.
See where Battle of Eskrador occurred on the galactic map during the Horus Heresy.