Minazuki Kobato

Mizuki's step-sister. After their parents died in an accident, she raised Mizuki single-handedly.

She is engaged to Shinji Idobata, a math teacher and colleague of Amahiko and Mizuki at Shosei Academy, where she also teaches physical education.

She falls from grace after surrendering her body to Amehiko in order to save Mizuki, who had fallen victim to his schemes. She is the homeroom teacher for both Mizuki and Amehiko.