The Legio Ulricon was a Traitor Titan Legion of the Dark Mechanicus that repudiated its oaths to the Emperor of Mankind and followed the Warmaster Horus into the service of the Ruinous Powers during the Horus Heresy. There is very little information in the Imperial records about this obscure Titan Legion, though it is suspected to have been founded before the Age of the Imperium, during the Age of Strife. The Legio Ulricon was known to have fought alongside the Night Lords Legion in the Thramas Crusade of the Horus Heresy, keeping the Dark Angels Legion at bay for over three standard years, so as to delay their deployment in support of the Loyalist cause on Terra. They were utterly devastated in a carefully coordinated ambush by the Dark Angels, who proceeded to destroy the Legio Ulricon'