As a teenager, Osanai is brusque and violent. He looks down on other delinquents not in his gang and is highly confident in his fighting abilities. He is also quite dim-witted, easily getting manipulated by Tetta Kisaki to do his bidding. After suffering from life as an adult, Osanai has become a shell of his former self. He turns into a meek and mild-mannered man who apologizes for anything he does and easily gets startled.