The president of Eiji's class. A bright, high-spirited and popular girl, her father is a newly rich self-made man and her family is tremendously wealthy. Thanks to her personality this upper class "princess" status of hers doesn't particularly show, though.

Born as a futanari, she got over her dislike for her body at an early age and came to be curious about all things sexual. With Natsuki as a partner she's been researching her sexuality almost nightly in the school infirmary. While already fully sexually experienced, she is constantly in search of further stimulus and pleasure.

Eiji's classmate. She sits next to him in class, and seems like a kind enough person. Due to trauma suffered in a sexual harassment incident in the past she became an obsessive-compulsive neat freak, and was violently ill-disposed toward members of the opposite sex; recently she has largely recovered and is fine with men around. Her personality has a cool and high-handed side, but once she takes to someone (boy or girl) she becomes quite intimate.

Regarding sex she knows what she's read in magazines and heard from the idle chatter of other girls, which sparked her interest in the subject. She has many hidden interest in this area, which it's up to Eiji to find out!

Eiji's classmate. Taken into Rumi's family by her father as a child, Natsuki was raised as his second natural daughter. However, her fierce devotion to Rumi has given her the appearance more of her maid than her sister.

At a glance she's the inscrutable, mysterious type. She doesn't talk much and doesn't let her emotions show, but due to the development of her body at Rumi's hand when she enters "H" mode she undergoes a complete change, to a brazen, dirty talking girl. Because Rumi has focused on her anal training, Natsumi is still a virgin. She alternates between sadistic and masochistic personalities at Rumi's command.

Rumi's step-brother, a year younger than the protagonist. His frail constitution, slender build and pale skin make him look remarkably girlish.

In love with his sister, in the past she caught him stealing her panties to use for dubious purposes and since then has been blackmailed into her service. He is now at her beck and call in her quest for sexual stimulation. He's still a virgin in all senses of the term, but is experienced in "petting level" play along with Natsuki and Rumi.