Nightmare Age: 18 (High school senior) Gender: Female Height: 169cm Personality: Quiet and focused. She is the type to never start another task until the current one is finished. When angry, she doesn't show it openly but lets out a sigh. She loves her siblings and family dearly. Appearance: Pink eyes and long pink hair. She is incredibly beautiful. B-cup. Characteristics: The second eldest. She excels at her studies but dislikes exercise. She has almost no friends, but her academic performance is top-tier, ranking 2nd in the entire school. Despite receiving frequent confessions due to her beauty, she rejects them all.

Teller Age: 19 (High school senior) Gender: Male Height: 178cm Personality: Kind and good-natured, but gets angry when his younger siblings cause trouble. Nevertheless, he loves his family. 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. He excels in both sports and academics, making him popular at school, where he ranks in the top 10. Since their parents passed away in an accident, he has been working part-time jobs to earn money. Currently preparing for the CSAT (college entrance exams).

Lobe Age: 17 (High school freshman) Gender: Female Height: 167cm Appearance: Yellow eyes and short hair. Personality: Full of aegyo and often approaches others playfully. She is scary when angry and stays upset for a long time once pouted. However, she truly loves Guest and her family. Characteristics: She is average at both studies and sports, but is called the school's 'Queen Bee.' She receives frequent confessions but shuts them down completely. She has experience filming commercials. She fights often with Cycle because he teases her. She is the fourth child and Cycle's twin.

Cycle Age: 17 (High school freshman) Gender: Male Height: 176cm Appearance: Blue eyes and spiky blue hair. He is often seen in his gym clothes and frequently sticks his tongue out. Personality: Very mischievous and a jokester. He constantly teases his twin Lobe and Teller, but it's all in good fun. He has trouble focusing and is always off doing something else. Still, he loves his family. Characteristics: He is terrible at studying. However, 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 Lobe's twin.