Fabian is a Mutant who refers to himself as the Emissary of the True Emperor and led the Church of the Abhorred on the Imperial world Siluria IV. The Church was later investigated and then attacked by the Witch Hunter Tyrus, who believed Fabian died in the attack. However Fabian had managed to escape and with the surviving members of the Church they attacked Siluria's spaceport, where they hijacked a ship and successfully escaped. Imperial reports now suggest that Fabian has embarked on a career of piracy and brigandage, and his forces prey on ships transversing the Imperium's space lanes. Tyrus has tried to apprehend Fabian on two further occasions, but he has thus far, failed to catch the Mutant leader.