Gods aren’t omnipotent on forgotten realms. In fact, is impossible to exist two omnipotent beings at the same time. Mainly when there are a conflict between then. Can a omnipotent being undo a thing made by another omnipotent being?.. To mention a Sorcerer’s Coven on Conan universe, as i’ve posted before
The White Hand of Hyperborea
Hyperborea is ruled by the White Hand, a coven of sorcerers not unlike the Black Ring of Stygia or the Scarlet Circle of Khitai. The White Hand “Witchmen” are the priests and priestesses of Louhi as well as accomplished sorcerers. Their magic focuses around the cold of their land and control of the dead. Hyperborean sorcerers are highly prized in the northern wilds, but they are little respected in Hyborian lands.
source Sorcerous Societies of the Hyborian Age
Note “as well as”, my idea of sorcery on Conan Exiles is by using corruption to corrupt the living and create undeads or bargain with demons for arcane knowledge. Also, you shouldn’t be able to worship Mithra and do demonology Demonology & Necromancy on Conan Exiles - #15 by L0rdVictor