She is Ibuki's younger sister and one of Yuki's aunts on his mother's side. She's betrothed to Senshirou. She hates most men, with the exception of Yuki and Senshirou.
She is one of the Giou Clan "Masters" who teach the Zweilts and others martial arts and similar skills. Her apprentice is Shinmei Masamune, who is a necromancer-in-training.
She is quite the doting aunt towards Yuki which is remarked upon quite a few times. Before even introducing herself she first tackles a confused Yuki into a hug and insists on kissing him when they first meet.