A third-year student and one of the "Two Great Onee-samas" of Kuou Academy along with Rias. Called the ultimate "Queen" by other members. Born between a human mother and fallen angel father, after the death of her mother, she became Rias' servant. She is a friend close enough to call Rias by her name in private, yet calls her Buchou in presence of others and displays a master-servant relationship in public. She persistently refuses to use her power of light, inherited from her father, but starts using it after being convinced by Issei.