Cyrion was a veteran of the Long War like the rest of 1st Claw, who took part in various campaigns during the Great Crusade and Horus Heresy, including the epic final battle during Siege of Terra. Cyrion possessed a psychic gift which allowed him to taste and feed upon fear. Cyrion secretly preyed upon Legion serfs and other mortals to satiate this thirst, which marked him out as a growing devotee of Slaanesh. Talos considered him valuable, but Cyrion was hated by the rest of 1st Claw for his Chaotic corruption. Cyrion gained an augmetic arm following the Crythe Campaign, which Abaddon the Despoiler had requested the participation of the Exalted's warband.