Mai is a transfer student and new to the Fuuka Academy. Ever since mother died, the main heroine has been taking care of her younger brother Takumi who is suffering from a heart condition, as a promise to her mother. Her child is named Kagutsuchi, a flaming dragon with sword in the middle of its head. When involved into battles, both of them can control fire and use it for a number of attacks. Mai hates to burden others with her troubles and therefore always tries to smile, hiding her own anxiety from her friends as well as from her brother.