Mimi Usa

Age: 10
Zodiac Sign: Capricorn
Height: 148 cm
Weight: 42 kg
Sizes: 80 - 68 - 78

Another of Rin's friends, Mimi is a quiet girl who is unusually well-developed for a third grader. She was picked on by Aoki's predecessor, and quit coming to school to protect herself. In revenge Rin wrote threatening notes to him that caused him to eventually quit due to "work-related stress". After Aoki takes on the job of teaching the class, he manages to convince Mimi to come back to class.

She is very studious and has a secret crush on Reiji.

In the end of the manga she convinced Reiji to answer her feelings.