Kyou Nukui

Kyou Nukui is a high school shut-in who spends his days creating and uploading music online. One day he gets a request from a fan to meet, and is understandably surprised when his fan turns out to be a ten-year-old girl named Jun. Now, he has the task of helping the young Jun and her sisters in their dream of forming their own band.

[Spoiler] During middle school, Kyou suffered from bullying after a classmate found his personal writing. Kyou refused to return to school afterward. [/Spoiler]