Kazuma Akazawa (赤沢 和馬, Akazawa Kazuma) is the older brother of Izumi Akazawa in the manga and cousin in the anime. He was an ex-student at Yomiyama North Middle School in 1996. He never appeared in the anime.

Kazuma has short black hair and black eyes. He and his younger sister, Izumi, look alike.

Kazuma is mentally unstable, and he often locks himself in his room, hitting and banging the wall. This is likely due to a past trauma, likely the death of his parents, a couple of years before the series had started.

Kazuma appears in Chapter 12 of the manga. He is shown hitting the wall with his fist, creating loud noises. He sneaks out of his room to get some food and drops a plate. This alerts Izumi, and she walks out of the room to check on him. As soon as he saw his sister, he murmured her name and fled back to his room, and continued creating noises. Later, he committed suicide by hanging himself in his room.

In the anime, the class list of 1996 has Kazuma's name on it, and this could indicate that he is dead in the anime. In Episode 10, Izumi is seen crying for him at the start. In Episode 12, it is revealed that he died a year and a half ago, prior to the time when Izumi met Kōichi Sakakibara.