Kazuki Tomori

Nao's older brother who is a member of a band. Previously had the ability to make air vibrate which he used on live perform to change his guitar sound. But the scientist did experiment on him and until now he stayed at the hospital. He didn't even recognize Nao as his little sister anymore.

He's the one who affect Nao being the fans of band ZHIEND.

[Spoiler] 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. [/Spoiler]