Leader of a Chaos Space Marine warband known as the Black Angels, Vorgath the Ruthless carved a bloody swath through the northern Imperium-controlled regions of the Eastern Fringe for almost four millennia. Vorgath's allegiance with the forces of Chaos seemed to be driven primarily by a mad, fanatical hatred for the Imperium of Man, rather than any true loyalty to the Gods of Chaos. He had absolutely no regard for the lives of those loyal to the God-Emperor of Mankind, encouraging his men to hunt them for sport or use them as a means to satisfy their most primal urges whenever possible.
Imperial records dating back to the 37th Millennium seem to indicate that Vorgath once led a Chapter of Space Marines tasked with defending the very worlds that he would later terrorize. With each passing century, more and more systems fell into his grasp, their populations being worked to extinction to provide the resources necessary to fuel further conquest. It seemed his violent rampage across the stars would not have ceased until Terra itself had been crushed beneath his boots, were it not for Captain Varrus of the Avenging Fists Third Company, who killed Vorgath during the Battle of Alnor in 505.M41.
In the wake of Vorgath's death, the remaining Black Angels reorganized themselves under a powerful Daemon Prince known only as "The Horror That Lurks Beyond The Sky". Since then they have resumed their crusade against the realms of Man, and have even taken part in the Second Tyrest War in 999.M41.