The Purifier Wars
The Purifier Wars is a campaign set in the far future, in the year 3488. Humanity has spread out into the galaxy, not as a unified force, but as a number of different factions. Genetic manipulation is commonplace, and humanity has combined it’s genetic code with a number of different terrestrial animals in order to better survive on the new worlds.
The source of the conflict in this campaign is the Purifier forces. Long ago, a large group of military fanatics chased a mutant warlord from the Core Worlds, and settled in a far-removed sector of the galaxy, where they continued to develop and improve their military and propulsion technology, while the Core Worlds lapsed into a long-lasting period of comfort and decadence.
Purifier dogma teaches that no form of humanity except for the pure-strain is acceptable. No mutations, no psykers, no variation from the pure homo sapien form is allowed. The Core Worlds have long since made peace with their variant-strain populations, and have embraced the new groups of psykers that have appeared over the last few centuries.