Paramyx was once the Chapter Master of the Sanctors of Terra, before they were deemed corrupted by the powerful Saint Basillius. The Sanctors and twenty-nine other Chapters were given the choice to take part in a Crusade within the Eye of Terror or to be destroyed. Choosing to redeem his Chapter, Paramyx led the Sanctors into the Eye, in what would become known as the Abyssal Crusade. There disaster would strike all the Chapters involved, with many becoming corrupted into the servants of Chaos. Paramyx and the Sanctors were no different and when they emerged from the Eye, they were reborn as the Blighted Claw warband, having dedicated themselves to the Chaos God Nurgle.
Paramyx now leads his Warband in spreading Nurgle's plagues across numerous worlds of the Imperium, including the Agri World of Gehöft. These plagues not only cause death amongst a world's population, but turn their victims into Plague Zombies which fall upon living. Currently his Warband's rampage of infection has made Paramyx, a target of the White Scar's Master of the Hunt Kor'sarro Khan, who now leads his Company in pursuit of the Blighted Claw. Kor'sarro has hunted Paramyx across half a Segmentum and has vowed he will claim the traitor's head no matter how long it takes.