He has medium length purple hair and blue-violet eyes. He is quite tall.
Initially, he seems to be a very jealous type of person which is shown when he was glaring at Miyamura when he talked to 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.
In the end, he becomes one of Miyamura's closest friends and accepts the fact that he and Hori have started dating.
He's commonly shown as "the normal one" out of all the characters, with his only odd characteristic being his dreams.
When Toru is introduced, it is quite clear that he has a crush on Hori. Although he tries to hide it, even Miyamura, who usually acts clueless about love notices. After he is rejected by Hori, he does not talk with her for a while, and when she tries to question him about Miyamura's first name, he runs away in tears. Despite this, he remains close friends with both Hori and Miyamura. Even though he has accepted Hori and Miyamura's relationship, he still appears to have lingering feelings for Hori, which occasionally leads to him feeling depressed or confused. Eventually, even these lingering feelings vanish as he begins his relationship with Yoshikawa.
Toru sees Miyamura as a close friend, and quite possibly a rival in love. Although he seems to have given up on Hori, so Miyamura can pursue her. They are quite close, and Toru knows Miyamura's secrets (his tattoos and piercings). He isn't afraid to laugh or tease when something embarrassing happens to Miyamura. He is also slightly jealous of Miyamura sometimes, which takes form in his nightmares, where he repeatedly kills Miyamura.
As Hori and Miyamura began their relationship, as their best friends, Ishikawa and Yoshikawa also began spend more time together. This leads them to becoming closer, until they begin to develop romantic feelings for each other. Although neither of them are aware of the other's feelings (Ishikawa believes that Yoshikawa doesn't like him, and Yoshikawa believes that Ishikawa actually likes Kouno), they agree to pretend like they're dating, ostensibly so that Yoshikawa can reject Yanagi's confession.
Things come to a head once Kouno confesses to Ishikawa. Yoshikawa, thinking that Ishikawa will accept Kouno and they were start dating, becomes depressed. Just as Yoshikawa is about to resign herself to this, Ishikawa tells her that he would turn down Kouno, and that he wants to continue being with Yoshikawa.
However, Ishikawa and Yoshikawa never officially start dating. Despite their mutual attraction and them liking each other, Yoshikawa's fears and concerns make her unable to fully commit to a relationship, so they stay in a sort of limbo where they're not quite dating, but they're definitely more than just friends. Ishikawa accepts this, but also says that he will do his best to try and make them fall in love with each other.
At first, Ishikawa is attracted towards Kouno, who is chasing after him. However, after spending a lot of time with Yoshikawa, Ishikawa finds that he's more attracted to her than Kouno. Eventually, despite (or maybe because of) Ishikawa and Yoshikawa pretending that they're dating, Kouno finally works up the courage to confess her feelings to Ishikawa. While Kouno says that she doesn't need a response, and that she only confessed to satisfy herself, Ishikawa says that he would have turned her down anyway. Afterwards, Ishikawa still is slightly attracted to Kouno, which only increases Yoshikawa's doubts about their relationship.
Ishikawa and Iura are childhood friends. Whenever Ishikawa isn't with Yoshikawa or Miyamura, there's a good chance he's with Iura. Having been together through elementary and middle school, Ishikawa is Iura's best friend and confident, and puts up with a lot of his jokes. However, as a result of this, Ishikawa tends to be extremely blunt with Iura, telling him to be quiet when he's too noisy (which is pretty often).