After escaping from his former master, Maul went into hiding in the Unknown Regions to begin building his power base on Dromund Kaas, a ghost-planet, abandoned thousands of years earlier when the Sith Empire of that era fell.
It was there that he formed his own Sith cult, in the tradition of those who came before him.
Few of his Cultists were force sensitive. The ones who had the potential to become a threat were killed for “blasphemy” Those who were not strong enough to ever surpass Maul in the force were given limited training in it.
Over the decades his cult became a powerful force, and Maul brought them out of hiding to take his vengeance upon both Jedi and Sith….