Takeshi is Touko's lover in the game. He studied abroad in America with her but returned to Japan 1 year earlier. After that, he started to work in the Tachibana General Laboratories, albeit in a different building from Touko's. There, Takeshi stopped consistently communicating with Touko, occasionally calling her and saying that he is busy. Eventually, Touko finds out that Takeshi is getting married.
Touko stated that Takeshi was positively different from her previous boyfriends, noting that he isn't a careless person and that she feels protected with him. Takeshi is smart and kind but not very talkative.
Impact on Touko
Takeshi was always very important to Touko. Before meeting him, she had a series of bad romances. Takeshi was the one person who supported Touko at the right time. She constantly thinks about him in her diaries and tries to avoid menial tasks at work, longing for a relationship with him. When she learns that her old friend Harumi is getting married, she becomes jealous and wants to hear a proposal from him.
However, upon hearing that Takeshi is getting married, Touko becomes extremely unstable and contemplates resigning from her job. She sinks into depression and blames herself for not recognizing that Takeshi had stopped loving her. Once, Touko encountered Takeshi in the laboratory, where the only thing he said was, "You look very good". In response, she burst into hysterical laughter, hoping that he would tell her about his marriage.