The Tchari were a Chaos Cult that began a rebellion on the Imperium world Atari sometime after the Great Rift's creation. When the Ultramarines Strike Force Fulminata later arrived to defend the world, the Cult moved to attack the manor of Planetary Governor de la Sario, whose DNA held the key to victory over the Space Marines. Only the ruler of Atari and their bloodline, could access the gene-vault that contained the codes for the world's orbiting weapon platforms and with them, the Cult could scour the world's surface. Despite the intervention of one of Fulminata's squadrons, the Tchari captured the Governor and were in the process of escaping with him, when the Strike Force's Captain, Demetrius, ordered an air strike which killed the Governor. Though the squadron sent to save the Governor failed, they were able to rescue his daughter and with her aid the Strike Force gained control of Atari's orbital weapon platforms and used them to destroy the Cult.