Fahrenheit

Fahrenheit is a Shinigami who has come to the human world in search of Dune, who is an old friend of his past. He has long, jet black hair and ochre eyes. He has large horns and a fair sized sickle which later on in the manga is discovered to be the thing that is holding back Fahrenheit. It seems that before he left for his job to be a shinigami, he ran away from Dune without saying "Good-bye". When he had to reap the soul of the child (who we would later find out is Moegi), he felt pity for her, and against the rules, he sealed himself inside Moegi, giving her a second chance of life. Ten yars later, Moegi becomes a student at Mitsuhachi Academy, where she coincidentaly encounters Dune. With great regret, Fahrenheit tries to tell Dune what he never got to say, but due to leaving the afterworld and abandoning his position (which is a sin to the Shinigami ways), he cannot speak when around Dune and is branded a devil. He is promised by the sickle that if he is to take the soul of Guilt-na-zan (whom it refers to as a red-eyed, silver-haired vampire), he can be free. Although he is a devil, he has to act like a normal high school girl, which is rather comical when he is doing things like knitting or acting rather feminine. As much as he sees Shizuka as a friend, he also sees her as a rival in getting Dune's attention. During his altercation with Guilt-na-zan, Guilt-na discovers that the sickle is what keeps Fahrenheit bound to the mission of Guilt-na's demise, and destroys it, freeing Fahrenheit and allowing him to reconnect with Dune. Wikipedia.