Hotaru Kumogakure is a ninja who joins her brother in a scheme to defeat Mamoru Kagemori, seeking vengeance for their clan's disgrace. This disgrace originated from their athletic meet loss to Yamame Hattori, caused by Hotaru’s distraction from Yamame’s fabricated UFO sighting. Upon first meeting Mamoru, Hotaru openly declares romantic feelings for him. These emotions directly shape her actions in battle, leading her to spare Mamoru despite having a clear finishing strike—prioritizing personal sentiment over clan objectives. When Mamoru is wounded fighting her brother, Hotaru saves him by administering her family’s secret medicine via mouth-to-mouth, enabling his recovery and subsequent victory. After the failed vengeance and conflict resolution, Hotaru relocates to Mamoru’s neighborhood and enrolls in his school, integrating into his daily life. Her design features hair ribbons and a ponytail. Promotional material depicts her alongside other female characters in settings like hot springs.