Katsuyuki Saigo

Saigō is a large, muscular young man who attends the same school as Kōshi and the rest of the main cast. He has a very threatening demeanor, communicating mostly in grunts and gestures and continuously wears sunglasses. He is the admired leader of a trio of hoodlums from Kōshi's class and apparently frequently gets into fights. Appearances are deceiving, however; Saigō is quite fond of kittens, of which he has several, and apparently reads romantic stories for enjoyment. When he first meets Alice Uzuki, he defends her against a large group of assassins without any concern for his own safety. Later, he takes a hit from Alice's guitar string weapon to protect Kōshi from harm.

He falls deeply in love with Alice and seeks help from Momoko and the other main cast to find a way to deepen their relationship.