The Cultists are radical, extremist offshoot of Adam Hale's White Faction and Marauder state. Their charismatic leader on the other hand, Adam Hale, has ties to the long vanquished Earth Defence Force and plays a major part in War of 2150 and particularly the Battle of Bakhuysen Trench when he first attempts to destroy the Terraformer. Whether the Cultists share a stronger link with the White Faction or whether Hale simply co-opts another group to suits his aims is unknown.
Under Hale's leadership, the Cultists goes to war with the Red Faction and force everyone to take shelter beneath the surface after destroying the Terraformer and wrecking the planet's weather. Hale is believed to have died during this battle and the threat the Cultists posed nullified, but he survived.
The Cultists, still lead by Adam Hale emerge once more after tricking Darius Mason into destroying the Seal and unleashing the Plague Armageddon upon Mars and the faction as a whole continued well the armageddon with some member likely surviving after the Plague threat is exterminated.