Riddle Rosehearts

Riddle Rosehearts is a second-year and the head of Heartslabyul. He strictly upholds strange rules made by the "Queen of Hearts." He's from a common yet famous family, because his parents are famous doctor mages. He's feared by the rest of the students because of his severe punishments towards those who break the rules. In the past, he endured very severe lessons from his mother. She convinced him that only by perfectly following the rules, even the most severe ones, could one become perfect and have friends. Riddle was very fragile as a child and wished to have a normal life like other children, as well as wanting to have friends.

Riddle's unique magic is called "Off with Your Head!" It causes a collar to lock around one's neck, sealing away their magic until he takes it off.

(Source: Twisted Wonderland Wiki)