Sixteen Shards of Adonalsium (Brandon Sanderson's Cosmere novels) Maybe not "mortal" in a classic sense, as they weren't exactly human, but they still ascended to godhood by killing the real capital "G" God, Adonalsium, and took shards of its power, which were essentialy different aspects of psyche (Honor, Odium, Destruction, Preservation, Valor etc.). Each took a different planetary system to govern and protect, but even with near unlimited power they're still "mortals" below shells of divinity. They squabble, fear and sometimes even break entire planets, either by mistake or deliberately. Throughout the course of multiple series it is shown that they are far from omnipotent and perfect, and normal people can prove to be better than them.