A member of " _mecha mecha mote te ru mondaiji sannin gumi_" or MM3 called by her classmate Kitagawa Mimi. Although he often skips class, he's a prodigy and his grades are very good. Ao, like his buddy Toujou Ushio, is also attracted to Mimi, but Mimi has only shown affections towards Toujou.

Spoiler

Later in the series, it was revealed that Ao has many sisters, and his sisters used to tease and play him by dolling up as a female, which is why Ao came to detest girls.