Black Crusade: The Screaming Vortex
Chem Hunter of Messia
Former naval officer, dissatisfied with the imperium for a long time. During a boarding attack his brother got executed for cowardice (unjustly in his eyes) by his commissar. He shot and killed the commissar, took his greatcoat, hat and bolt pistol as he fled the ship. Landed his stolen flyer on a nearby planet and from there on has sworn vengeance on the imperium for its tyrannical oppression of its citizens.
After fleeing to the Screaming vortex landed on Messia and became involved with the local Chem Hunters and developed a craving for certain chemicals. After a couple of years came across Prince Rayleigh and took this opportunity to escape the sands of Messia. After murdering his way through the ranks of the officers became close allies to Rayleigh.