Crimson Crusade

History
During the joint Crimson Crusade conducted by both the Death Templars and Star Reapers Chapters into the Golgenna Reach within the Calixis Sector, the two Space Marine Chapters found themselves heavily engaged against the large Death Guard traitor warband of Blight-Master Ussalax, upon the inhospitable feral world of Dusk. Ussalax is a vile Chaos Sorcerer that served within the inner circle of the Daemon Primarch Mortarion. Blight-Master Ussalax travels from one warzone to the next, unleashing his vile plagues upon the innocent and harvesting the bodies of the victims. Both Chapters finally managed to run the elusive Chaos Sorcerer to ground upon the world of Dusk. As both sides engaged one another within the swamps that covered the planet, they were set upon by the first elements of a splinter Hive Fleet of Tyranids.

Beset on both sides by the foul Plague Marines of Blight-Master Ussalax, and deadly Tyranid bioforms, both Chapters prepared to sell their lives dearly. With both their forces depleted to their mortis threshold, reports of strange black-armoured Space Marines bearing symbols of death and covered in burning flames began to crop up. Soon, both the enemy forces were beset upon, as squad after squad of black-clad Space Marines emerged from the swamp's rising mists, forming a cordon around the surviving Death Templars and Star Reapers. The relentless pounding of their bolters and the billowing flames of their heavy weapons blasted back the Tyranid bioforms scuttling around them, as well as making short work of the foul forces of Blight-Master Ussalax. The invading swarm and Traitor legionaries were shattered, dispersed and hunted to extinction. The surviving Chapter battle-brothers soon realized they had been saved by none other than the mysterious spectres known as the Legion of the Damned. The whereabouts of Blight-Master Ussalax remains unknown.