Kurumi Sahana

The school's mysterious new transfer student. She is quiet and self content, but is also Hideo's "master". She has a frail frame, short black hair, a small bust, and few inhibitions. Kurumi plays at naivety, yet is well aware of Hideo's attraction to her. She joins the Roman club to be closer to Hideo. She tortures Aiba by getting him to the brink of orgasm, but refuses to let him ejaculate. She lives alone, only letting Hideo in on this secret. Not much is known about her past or her family background except it is hinted that her parents are dead and that she lived in an orphanage with her siblings.

(Source: Wikipedia)