The cult of the Three Flames
The three flames existed since the dawn of times, the White Flame symbolizes order, purity, unchanging eternity, and the celestial gods, the Everflame burns eternally and brings change but still remains constant symbolizing the mortal races, and the Black Flame symbolizes chaos, mutation, rebellion and the demons.
The cult of the Three Flames is an old religion considered Heretical in the Empire of the White Flame and many other realms due to their worship of the Black Flame, intrinsically connected to the abyss and its denizens the demons.
The cult is not strictly evil although some of its members certainly are, but the majority seek to find a balance between the three flames and value them all equally.