Saiki Kusuo

Hairo is the class representative of Kusuo's class. He is a hot-blooded young man who is reliable and gets along well with everyone even towards the outcasts like Kusuo and his circle of friends. Despite finding Kineshi overbearing at time, Kusuo does respect his strong will and how well liked he is in school. But still find him annoying by his wild nature, but somewhat got used to him.

Nendou Riki

For Hairo, Nendou for him is a rival in terms of sports and strengths. Nendou is usually lax in terms of Physical Education but Hairo usually challenges him resulting in Nendou winning.

Kuboyasu Aren

Hairo treated Aren with his usual kindness though he was working out like usual, Aren was put off by the latter's energetic nature and decided it was best to avoid him though he was surprised at Hairo's popularity. However, when other classmates talked about Aren, Hairo stood up for him and said words that sounded like Aren's old leader. This caused Aren to respect Hairo who became the first that he wanted to be friends with.