Yukihana

Yukihana makes her first appearance in volume three of the novels. She is a ninja who works under Tamamo at her hot-spring hotel. She has an honest personality. In volume seven of the novels, she becomes a teacher for the handicapped at Kouta's school. When working as a teacher, she goes by the name Hanadai Yukino, and if someone calls out to her using the name Yukihana, she will say she is not that person. She can manipulate snow storms and uses a gleaming sword in battle; she is very strong.

Source: Wikipedia.