Meros

Meros was apothecary of the Blood Angels Ninth, a Baalite line-medic who walked into a daemon's bargain on Signus Prime so Sanguinius would not have to. He cut out his own gene-seed first. That was the last clean surgical act of his life, and the last time the Ninth could still call him brother without flinching.

The Ragefire took the rest. What left the cathedral was the Red Angel, a loyalist's face worn as an insult, a company apothecary turned into the thing his primarch had been tempted to become. Signus got its victory in the worst currency Baal has ever spent.

He did not remain a Blood Angel except as a wound. The daemon that used him kept the name like a trophy. Baal still claims the apothecary. The warp claims the Angel. Both are telling a true story about the same man, and neither will share the body.