Ollerus

He has been called the mage closest to becoming a "majin," a "God of Magic." He is a mysterious fellow, and by far one of the strongest characters in the series. He has a kind heart, he squandered the once in 10,000 year chance to become a "majin" (or magician god - one whose magical power has reached the level of divinity and can bend all natural laws) in order to save a cat. He also destroyed a human trafficking organization and saved 100 children, when he did not need to.