The Malstrain is an insidious mutation of the Genestealer Curse. Experiments meant to create a vaccine against the xenos plague merely warped it into something new and terrible, an alien cancer that still lurks within Hive Secundus. The Genestealers of the Malstrain are terrible evolutionary missteps possessed of extreme speed and aggression, capable tearing a full-grown Goliath into bloody meat in seconds. They accompany the gangs and Brood Scum they have infected, joined by Malstrain Tyramites – overgrown insectoid parasites, bloated on Malstrain infection, who follow their chosen masters like faithful chittering hounds.