- Konoha: Konoha was originally a video game character Haruka designed. However, following an unintentional wish made by him to be reborn the body of Konoha, which he had designed as his own "ideal body", the Snake of Awakening Eyes took on Konoha's form, forcing Haruka to stay in the Heat Haze while the other would be reborn in his stead.. Haruka can view and hear what Konoha experiences.
- Takane "Ene" Enomoto: Haruka's former classmate and first friend who he usually spent his time with. She was in love with him. Whether he had feelings for her or not is not revealed, although, it was heavily implied that he reciprocated her feelings, and that he would have liked to confess to her ("I wish I could have told that girl who used to be angry at me...")She is the person he hates to make worry the most; Haruka repeats several times how much he hates to make her cry because of his weak body. She is also implied to be his drawing muse ("Actually, I don't need a picture of her. I remember everything of her. I can imagine her in detail without anything. Without the picture, I can draw her.")His last thoughts, both in Mekakucity Actors and the novel series, are about Takane. ("I want to see you, Takane.") ("That's why, Takane... don't cry anymore.")As seen in -In a Daze-, Ene is later shown to have recognized Konoha during the accident on the streets and is prepared to chase after him with Shintaro when he is brought away with Hibiya in an ambulance truck.In -the children reason-, she expresses her feelings and memories of him after two years to him, but Konoha does not remember any of it. It seems Ene refuses to think of him as "Haruka" and calls him an impostor instead.
- Kenjirou Tateyama: Haruka's and Takane's former teacher. He once stayed over at his teacher's house for a few nights in order to complete a game for the cultural festival. They used to be in good terms and Haruka thought of him as the only adult he could speak honestly with.
- Ayano Tateyama: Haruka, like Takane, was a school friend of Ayano. In one scene, it is showed that he helped tutor her because of her poor grades. She supported Haruka and Takane to become a couple.
- Shintaro Kisaragi: Haruka (along with Takane) used to spend time with Shintaro. Haruka would ask Shintaro to teach him how to play video games so he could play along with Takane. During that time, they grow close.
- Azami: Azami has once spoken to Haruka before the creation of Konoha. Although it was not his intention, Azami granted his wish to have Konoha reborn in his stead.