Karin Yuuki

Number 4 of UQ Holder's immortal squad, Numbers. She is very devoted to Yukihime after having been saved by her in the past and is jealous of Touta's close relationship with her. Her immortality is said to come from divine origin, as all her wounds heal instantly instead of just regenerating fast like in most immortals. Because of it she was branded as a witch and hunted when she was a small child centuries ago.

(Source: Wikipedia)