Tsubaki Mapputatsu

Tsubaki is a miko swordswoman. She was first hired by the yakuza boss in order avenge his earlier defeat at Mamorus hands. She is pursuing them for the sake of justice. After finding out the truth about the yakuza boss she takes revenge on that boss. She also decides to enter Mamorus school. After Mamoru cheers her up while she was depressed about being oldfashioned she begins to develop feelings for him. Taken from Wikipedia