Ozma

Ozma was an ancient warrior and was introduced in "The Lost Fable". He rescued Salem from her imprisonment in a tower, and both eventually fell in love with the other. Eventually, Ozma fell ill and died, and Salem set out to convince the Gods to resurrect her lover. Ozma was revived by the God of Darkness, but killed again by the God of Light soon after. Ozma was eventually given a choice by the God of Light before he abandoned Remnant; he would be able to return to the land of the living to act as a guide for Humanity and would protect Relics, powerful items that once brought together would bring the Gods back to Remnant.

He was given the ability to reincarnate after death, joining souls with another like-minded person so that he would never be alone. After returning to the world, Ozma reunited with Salem. The two acted as Gods and created a prosperous kingdom while also starting a family, but they turned on each other after Ozma displayed his disagreement with Salem's plans for Humanity. Their children were killed in the ensuing battle and Salem murdered Ozma, who reincarnated again. Thus began the centuries-long feud between the two, with Ozma making it his mission to protect the world from her evil.

At the start of RWBY, Ozma's current incarnation was Professor Ozpin, the Headmaster of Beacon Academy. Following Ozpin's death at the hands of Cinder Fall during the Battle of Beacon, Ozma/Ozpin's soul joined with Oscar Pine.