Aoi is a classmate of Sumika, Ushio and the rest's.
She developes a crush on Sumika and starts hanging out with her and her friends when, after having her first kiss stolen by Tomoe and being ganged up on by her classmates, she's driven to run out of class. Sumika follows her and comforts her.
Aoi is a gushing fan of the yuri light novels penned by Ushio's brother and a member of his fanclub (though she believes the author is a sensitve, beautiful woman and has no idea of his real identity. Sumika and Ushio desire to keep it that way). Aoi draws doujinshi for his books, but is inspired to create her own original yuri romance and wants to do so with Sumika. She becomes extremely saddened when Sumika at first is reluctant, to the concern of her parents, but ends up helped and again comforted by her in the end.
At first, she is convinced that she and Sumika have a mutual love for each other, and thus hangs around her like a lost puppy. Ushio, on the other hand, wants to stay as far away from Aoi as possible, which causes a problem for Sumika who wants to spend time with Ushio. Eventually, Ushio and Sumika are allowed to spend time alone, and when Aoi sees them together, her heart is broken and she realizes she was just getting in the way. Even so, she cannot stop loving Sumika.
