From beyond, a soul descends

Ozma, a powerful wizard of old, back when magic was everywhere in Remnant. He who was cursed by a god to always reincarnate into another body each time he dies, where he will slowly take over the host like a spiritual parasite. Until he defeats the woman he once called wife and love.

But suddenly, through unknown means, the wizard gets a taste of his own medicine, as his own mind and body are completely taken over by another soul from another universe. One with knowledge Oz could only hope to achieve.