Aya Iseshima  

The main character of the series is Aya, a high school junior with exceptional martial arts skills. Despite being an excellent fighter, Aya tries to conceal this talent from others. It appears that she has feelings for Natsumes older brother, Haruki, but keeps these emotions hidden. Aya enters the Platonic Heart contest in hopes of finding her missing friend, Miko. She believes that winning the competition will lead to Mikos safe return. Later on, it becomes apparent that Aya is a ruthless killer and a berserker who will stop at nothing to defeat her opponents.