A bunch of nutters that decided to summon Kasyrra for their own selfish and delusional ends. Cult members kidnapped Cait's sister, Calla, as part of their ritual for Kasyrra, as the demoness required someone who was "pure" like Calla for her plans. The cult members involved in the ritual were led by Master Tollus. The cult sent Calla through a portal, and in exchange they received an object resembling a case that Master Tollus took. The cult members were disturbed by the Player Character and Cait, and fled after completing the ritual, heading up the hill to the Warpstone atop it. Shortly after, Kasyrra came through the portal.
After the tutorial, the next time the Player can encounter the Demon Cult is in Harvest Valley, directly south of Hawkethorne. Under Kassyra's orders, Master Tollus has directed his underlings to various ends including but not limited to: corrupting the local centaurs and bringing them under Kasyrra's control, kidnapping and harassing the locals, and capturing key infrastructure points such as water pumps, river fordings, and the local mill. The Player is expected to be able to confront him again in the centaurs' territory, using the chieftain as a puppet to control the tribe.