Hatsumi Narita

The main character of the series; she is really close to her older brother, Shinogu. At the beginning of the series she is a second-year student at Takazono High School, a private school. While Akane's fear of being pregnant leads Hatsumi into purchasing a pregnancy test for her, Ryoki accidentally sees her with it, and in exchange for that information's secrecy, Hatsumi becomes Ryoki's personal slave. She'll believe anything you'll say to her.

(Source: Wikipedia)