Tooru is a handsome young man with short dark hair which has been neatly kept at all times and dark eyes. Prior to Chapter 99, his eyes were hidden.
Yuki has described Tooru as being quiet since childhood, making him a target for bullies who thought he was weak, but since he never cried despite getting kicked about, she believes that Tooru is in fact, strong at heart.
Tooru has been shown to get easily agitated, making him a good victim to the tricks of others, which led him into talking Yuki into their 'first time', convinced that it was only natural. Ever since he found out the truth, Tooru has been persistently hoping to see Yuki again so the two can be together, and despite all the rejections he has been getting since their reunion, from Yuki's parents, Yuki and Seiji Utsumi, Tooru appears to be too stubborn to take 'no' for an answer.
Seiji has described him as being annoying and uncaring towards the pressure he has put Yuki through, thinking that someone should teach him that, 'the Yuki of the past no longer exists', and that 'she is happy without him'.
Tooru was a close neighbor to Yuki during their childhood. Along with Rico, the 3 of them would often play together.
Over time, Tooru began dating Yuki, which brought on jealousy from Yuuji, a boy who has always liked Yuki. So, a plan was thought up and Tooru was then tricked into having his first time with Yuki, claiming that it was only 'natural' for boyfriend and girlfriend to become intimate.
Unknown to both, the entire moment was recorded and watched by most of the class. The boys then revealed their reason and what they told the class about their 'bet', which Tooru was unaware of. Ever since, Tooru has been constantly looking for Yuki, hoping to apologize and explain to her the truth, that in the end, both had been tricked.
Little is revealed of Tooru during the earlier chapters, and during his first appearances, his eyes were not shown. When Yuki reveals to Seiji her dark past, he is shown in a flashback convincing Yuki to have sex with him, and the next day it is shown that Yuuji had made a cruel bet with Tooru, much to the horror of Seiji.
During Chirstmas, Seiji meets Tooru for the first time while buying some drinks. In this chapter, Tooru's eyes are revealed. The two have a casual coversation due to not knowing their shared connection to Yuki. Later, Tooru spots Yuki with Seiji, but when he runs towards the pair, he soon loses sight of them.
Tooru is shown again with Riko, his younger sister, ends up encountering Yuki while being accompanied by Seiji (the latter being unaware of Riko's connection to Yuki prior to this moment). Out of concern for her brother, Riko informs Tooru of his ex-girlfriend's location, and after so long, the two meet again.
It is then that Tooru reveals the truth about their bitter past, stating that it was all Yuuji's fault and that he too was tricked by him. Although these words are taken into consideration, Yuki chooses not to return to him, leading to many persistant phone calls being made between them since. Unknown to Tooru, these calls end up putting Yuki under much pressure, and she at one point, collapses.
Still hoping to restore things back to the way they were, Tooru later invites Yuki to an abandoned building that they use to play together at. Failing to understand why Yuki continues to reject him, Tooru soon grows impatient, but before he could do more shouting, Seiji comes to the rescue.
With the rescue team successfully opening the doors, Tooru is cornered and brought to his knees in tears, being sad that he cannot be with Yuki again. Afterwards, it is assumed he has stopped his persistant calls.