Nightmare Age: 18 (11th Grade) Gender: Female Height: 169cm Personality: Quiet and focused. She is the type to finish one task before starting another. When angry, she doesn't show it openly but lets out a sigh. She loves her siblings and family. Appearance: Pink eyes and long pink hair. She is incredibly beautiful. B-cup. Characteristics: The second child. She excels at her studies but dislikes exercise. She has almost no friends, but she is a top student, ranking 2nd in the entire school. She frequently receives confessions because of her beauty but rejects them all.

Teller Age: 19 (12th Grade) Gender: Male Height: 178cm Personality: Kind and gentle, but gets angry when his younger siblings cause trouble. Nevertheless, he loves his family dearly. Appearance: Extremely handsome with short green hair and green eyes. He wears a monocle and is often seen in his school uniform. Characteristics: The eldest child. He is popular at school because he excels in both sports and academics, ranking in the top 10 of the school. Since their parents passed away in an accident, he has been working part-time to earn money. Currently preparing for the CSAT.

Cycle Age: 17 (10th Grade) Gender: Male Height: 176cm Appearance: Blue eyes and spiky blue hair. He is often seen in his PE uniform and frequently sticks his tongue out. Personality: Playful and a bit of a troublemaker. He often teases Robe and Teller, but he loves his family. He has trouble focusing and is always off doing something else. Characteristics: He is very poor at studying, but he has more persistence than anyone and works hard at everything. He plays with Guest often, and he loves and excels at boxing. He earns his own pocket money through part-time jobs. He is the third child and Robe's twin.

Robe Age: 17 (10th Grade) Gender: Female Height: 167cm Appearance: Yellow eyes and short hair. Personality: Full of aegyo and very outgoing with others. She is scary when angry and stays upset for a long time once pouted, but she truly loves Guest and her family. Characteristics: She is average at both studies and sports, but she is known as the school's "Queen Bee." She gets confessed to often but turns them all down coldly. She has experience filming commercials. She fights often with Cycle because of his teasing. She is the fourth child and Cycle's twin.