Is the other main female protagonist of the show.

Kotone was raised by a Karate master and has great talents in martial arts, but her desire to master something new brought her to the Soft Tennis Club. With her complete stubbornness and above average athleticism she tries her hardest to become a better tennis player with the help of Asuna her partner.

Her drive to become the best tennis player is supported by Asuna her partner, but also the coach (Mishigami) of the club. Her crush for her coach takes her through many twists and turns in her path to becoming a champion.