Cyrion was a Tactical Marine in the 1st Claw (Squad) of the 10th Company of the Night Lords Traitor Legion. He was of Nostraman birth and took part in the Great Crusade, Horus Heresy, and the Long War that followed. By the time of the 41st Millenium he was serving under Talos Valcoran aboard the Covenant of Blood, captained by his former Sergeant, the Possessed Chaos Space Marine known as "The Exalted". Talos was subject to the manipulations of his immediate superior, as well as those of the powerful Chaos Lord Abaddon the Despoiler, which placed him and his warriors in mortal danger time and again.
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 the 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, an offensive where Abaddon the Despoiler had requested the participation of The Exalted's warband.
Despite surviving an almost fatal encounter with fellow 1st Claw squad member Uzas, largely due to Cyrion tricking Talos Valcoran into killing the berzerker, he was still slain by the Void Stalker on Tsagualsa.
Despite his psychic gift, a result of his taint by Slaanesh, Cyrion stood with his fellow Night Lords in the belief that Chaos and the corruption that it induced were assured, yet not needed for victory in the Long War. However, over time, as his corruption and selfish pursuit of pleasure grew with Slaanesh's hold over him, Cyrion's goals became far more self-serving and manipulative, often causing harm or trouble to his fellow squad members.
- Artificer Armour - Cyrion's Power Armour was an amalgamation of scavenged pieces won in battle or taken from the bodies of fallen brothers of the Night Lords Legion.
- Legion Gladius
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- Blood Reaver (Novel) by Aaron Dembski-Bowden
- Void Stalker (Novel) by Aaron Dembski-Bowden