Kazuki Tomori

Nao's older brother who was a member of a band. Previously, he had the ability to make air vibrate which he used on live performances to change his guitar sound. But scientists experimented on him, and now he stays at the hospital. He didn't even recognize Nao as his little sister anymore.

He's the reason that Nao is a fan of band ZHIEND.

In episode 8, due to the singing from the lead vocalist of ZHIEND he calms down. During this time, Yuu Otosaka speaks with him, which leads him to remembering Nao.