Raijin

Raijin (雷神, Raijin) is a, now rogue, Shinigami of Division 2 that long ago fled to the World of the Living and has been residing in the Himalaya Mountains ever since. Originally a minor character during the second part of the series, it was revealed at the end of Book II that Raijin was behind the delicate manipulation of having Saki's soul reincarnate into Sadao Hashimoto. He is the antagonist in both Book II and Book III of the Soul Mate-series, despite being officially stated at such during the first chapters of Book III.

Trivia

 * Raijin's name comes from the Japanese god of thunder