Sevastus Acheran

Sevastus Acheran was the first Primaris Space Marine to command the Ultramarines Second Company, following the disappearance of Cato Sicarius. He assumed the captaincy near Terra after Sicarius vanished into the Great Rift, and retained it when Sicarius returned during the Plague Wars. Throughout the Indomitus Crusade he demonstrated that he was a substantive commander rather than a temporary appointee.

Acheran fought on Nemendghast, in Ultramar and in the Recidious System. In the last of these he reinstated Demetrian Titus as a lieutenant, and he observed him with the wariness that the Inquisition had taught the Chapter. After Demerium he offered commendation. On the hive world of Trygg, a Genestealer Cult destroyed the strike force. Acheran sealed the capital and died there, and Chairon died with him.

Titus succeeded him in command of the company. The Second Company continues to fight as though Acheran had issued its most recent order. His tenure is notable as the first held by a Primaris Space Marine, and as one in which a replacement commander established himself as captain in his own right.