Quori
Quori are a race of fiends native to the Eberron setting of Dungeons & Dragons; residents of Dal Quor, the Plane of Dreams in the Orrery, they are living nightmares, embodiments of the various fears and phobias that haunt the collective subconsciousness of all mortals.
They have basically conquered the continent of Sarlona, the birthplace of humanity, through a centuries-long manipulation of its population into the acceptance of psionics to create a psy-based religion called the Path of Inspiration; they hope to use this to prevent a fundamental shift in the nature of Dal Quor which they believe will transform the Quori into a completely new kind of dream spirit, the notion of which terrifies them.
There is a faction of Quori who believe that Dal Quor's transformation should be embraced, and who have rejected evil. These quori created the Path of Light religion, and sought refuge from their enemies in mainstream quori society by fusing with human psionicists, creating the kalashtar race.