Naruto: Clash of Ninja/Haku

Haku is Zabuza Momochi's right hand man and most faithful follower. He has a heavily androgynous appearance, so much so that when Naruto Uzumaki first meets Haku he ends up mistaking him for a girl, saying that "he's prettier than Sakura!". Before he started working for Zabuza, Haku lived as an orphan. His father killed his mother when it was discovered that she possessed a genetic ability, and his father would have done the same to Haku if Haku had not killed his father first. After wandering from place to place for a time he was found by Zabuza. He recognized Haku's talents and agreed to take him in as a tool. As a result, Haku becomes unquestioningly protective of and loyal to Zabuza, and only by being useful does he find a purpose in life. He ultimately gives his life in his mission to be useful to Zabuza, becoming a human shield to protect his master from Kakashi Hatake's Lightning Blade.