sDeep in the caverns used by the Demon-worshipping Cult, an ancient earthquake revealed bits of a ruined temple entombed deep within the mountain. Beyond the private chambers of the Cult's leader (Top Left,) a deep crevasse bisects both the cavern and the ruins. The cultists have set up a series of makeshift bridges to allow them access to the other side and set up a series of hastily constructed traps and barriers dissuade would-be visitors. Within the Temple Ruins themselves lie a burial chamber that the cultists have converted into an alchemy lab (Top Middle Right.) Across the hall is the object of the Cult's fascination: an elaborate altar above which floats a dark otherworldly crystal of some kind. The altar feeds energy to the crystal, which in turn exudes a mass of slowly-expanding dark webbing. To the side of the chamber, an old summoning circle retains most of its original function and is used by the Cult leaders to bring forth outsiders to do their dark bidding. The remains of several of the cult's victims are strewn about, left to lie in the pools of their own blood after becoming sacrifices to the Cult's dark masters.
The entrance to the cult hideout can be found here: https://inkarnate.com/m/o68z5V--cultist-hideout/