Sebastien was Chaplain Augustus' brother in their former lives, before the trials, before the change, before the thirst. Sebastien alone was at Augustus' side when the rest of their successor chapter was lost, the brothers escaping the cataclysm that claimed the entire host of the original Angels Cruentus. Through time and scavenging they rebuilt their chapter to a strength of just one company. When the first company, forever renamed the lost company, was sent on its first full mission back into the galaxy Sebastien led their ragtag band of battle brothers. There he lost all but a shred of his life, on the fields of that Eldar craftworld. All was not lost, after the battle the lost company had added a techmarine and Dreadnought husk from the Angels Vermillion to their ranks. Two years later Sebastien was reborn, interned in the metal sarcophagus of a Dreadnought. Together he and Augustus will see their chapter's torch kept aflame. Sebastien is the Angels Cruentus' greatest warrior, their strongest brother, their champion.

Furioso Dreadnought from my army "The Angels Cruentus"