Ким А Хин

One of the Four Guardians of Heaven, the "White Tiger", and was mistaken as Ee-jung by Woo-hyun, who had bullied her when they were little because of her appearance and her mother's ill-reputation. She is the friend of Dong-young and is also a student at Dong-young's school in order to protect her and to prevent her identity from being discovered by the other two Guardians of Heaven who were sent to capture the angel princess. Ee-jung's older sister, she cares for her brother dearly and tries to make him enjoy himself more. Despite having been bullied by Woo-hyun and saying she'd never talk to him again, Ah-hin seems to have some feelings for him, and later goes out with him. ~Wikipedia~