Initially, Tooru seems to be a very jealous type of person, which is shown when he glares at Izumi Miyamura when he talks to Kyouko Hori.

He has a very explosive temper, as seen in Chapter 12 when he ends up fighting with Miyamura when he (Miyamura) kept waving off Ishikawa's constant pressing on of his theories on whether or not Hori has a crush on Miyamura. However, he expresses regret about losing his temper after the fight.Ultimately, he becomes one of Miyamura's closest friends.