Hotaru Kumogakure

Hotaru is a ninja. She confesses her love to Mamoru when they first meet. She and her brother are scheming to defeat Mamoru (a member of the strongest ninja clan) in order to avenge their clan's disgrace in losing to Yamame at a ninja athletic meet. Her feelings for him prevent her from finishing off the wounded Mamoru and she instead administers some of her family's secret medicine mouth-to-mouth thus allowing him to defeat her brother. Afterwards, she moves into the neighborhood and starts attending the same school.