The Black Skull is a Renegade Warband of Chaos Space Marines of unknown origins and Founding. Only the core of the Black Skull are Space Marines, comprised of turncoats from many disparate Chapters united by their self-serving nature. The remainder of their number are comprised of Chaos Cultists. They are thought to be loyal to Chaos Undivided. Little else is known of their actions in current Imperial records.
When the Crimson Sabres Chapter began their descent into madness, they were determined to sell themselves dearly, and so, they turned to the Eye of Terror where they planned to die fighting the enemies of Mankind and in doing so reclaim their honour. The planet known as Nebulon was one of the outermost of the planets ringing the Eye of Terror, a world only occasionally veiled within that region. Onto that bleak orb swept the Crimson Sabres like avenging angels. In a twisted land of derelict hives the red-armoured Space Marines hunted and gunned down any quarry they could find. None could stand before them -- none, that is, until the Black Skull renegades emerged out of the stygian depths of the underhive. The two forces clashed, both nigh on Chapter strength, however, only the core of the Black Skull were Space Marines. The Crimson Sabres fought as one unifying force, and were able to overcome the renegade warband.
- The Renegade Wars (929-938.M41) - When the Renegade Crimson Sabres flee the Imperium into the Eye of Terror, they fight and destroy countless cults, but also face many warbands of Chaos Space Marine renegades within the Eye. They first engage and defeat the Black Skulls upon the world of Nebulon, and go on to face numerous other warbands that have been forgotten by history.
The Black Skull's colours are not listed in current Imperial records.
The Black Skull's badge is not listed in current Imperial records.
- Crimson Slaughter - A Codex: Chaos Space Marines Supplement (Ebook), pp. 30-31, 85