Codex: Dark Angels (2013), p23 — History of the Dark Angels

101.M34 Noble Passing

While leading his Chapter to victory in the Bloodpox Campaign against the Death Guard and the Brotherhood of Plague, the twelfth Supreme Grand Master of the Dark Angels, the esteemed Armaros contracts the loathsome pox. His rapid deformation convinces the Supreme Grand Master to immediately pass the Lion Helm to his successor. To ensure the contamination does not spread, Armaros voluntarily enters the Rock's reactor chamber and is wholly consumed.