Tagas was a member of the Blood Angels during the Great Crusade. Serving as Captain of the 111th Company, Tagas was badly wounded during the War on Murder. Somehow his body was recovered by Fabius Bile, who put Tagas into a vegetative state and experimented on him. Erebus found out about this, and during the planning for the ambush of the Blood Angels at Signus Prime, he convinced Bile to give him Tagas' body. Tagas was used to power Erebus' infernal demonic device known as the Ragefire.