Karsus's avatar

The notes regarding the essence of Karsus's Avatar were nowhere to be found. It is believed Mystra, the reincarnated form of Mystryl, snatched the spell information from the ruins of Karsus’s enclave and sent it on an eternal journey to the ends of the universe. This spell allowed the caster to become a god of his choosing, replacing a current god with himself the moment the spell was completed.

Whether the gods received a saving throw, were aware of its casting, and other factors were unknown. Karsus spent well over a decade researching this spell. It was so complex that he had to use a stone-filled gizzard of a gold dragon and part of the epidermis of the pituitary gland of the Tarrasque just to enchant one of the material components of the spell.