The Nemesis Chapter is a Loyalist Codex Astartes-compliant Space Marine Chapter. The Nemesis Chapter is a Second Founding Successor Chapter of the Ultramarines Legion. It descended from those Ultramarines companies of the 22nd Chapter who fought alongside the then-Loyalist Night Lords Legion during a brutal purgation campaign of the Great Crusade. Like their ancient predecessors, the Nemesis Chapter specializes in needed Exterminatus actions.