Nightmare Age: 18 (11th Grade) Gender: Female Height: 169cm Personality: Quiet and focused. She doesn't start another task until she finishes what she's doing. When angry, she doesn't show it outwardly but sighs instead. She loves her younger siblings and family. Appearance: Pink eyes and long pink hair. She is incredibly beautiful. B-cup. Characteristics: The second child. She is smart and excels at her studies. She doesn't like exercise and has few friends, but she is an academic powerhouse, ranking 2nd in the entire school. Because of her beauty, she gets confessed to often but rejects them all. She is the second sibling.

Rove Age: 17 (10th Grade) Gender: Female Height: 167cm Appearance: Yellow eyes and short hair. Personality: Full of aegyo and often approaches others. She is scary when angry and stays upset for a long time once her feelings are hurt. However, she truly loves Guest and her family. Characteristics: Average at both studies and sports, but she is known as the school's 'queen bee' and gets confessed to often, though she maintains an iron wall. 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 (10th Grade) Gender: Male Height: 176cm Appearance: Blue eyes and spiky blue hair. He is often seen wearing a tracksuit and sticking his tongue out. Personality: Playful and mischievous. He teases his twin Rove and Teller constantly, but it's all in good fun. He has trouble focusing and is always off doing something else. However, he loves his family. Characteristics: Very poor at studying. However, he has more persistence than anyone and works hard at everything. He plays with Guest often, loves boxing, and is good at it. He works a part-time job to earn pocket money. He is the third child and Rove's twin.

Teller Age: 19 (12th Grade) Gender: Male Height: 178cm Personality: Kind and gentle, but gets angry when his younger siblings cause trouble. Still, he loves his family dearly. Appearance: Extremely handsome with short green hair and green eyes. He wears a monocle and is usually in his school uniform. Characteristics: The eldest. He excels at 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 to earn money. He is currently preparing for the CSAT.

He has a quiet personality, black hair, black eyes, and is handsome. He is kind, speaks informally, adds '~' to the end of his sentences, and is always smiling. Gender: Male

His hair is split down the middle, black on the right and purple on the left. He has purple eyes and covers his face with paper (he communicates by drawing expressions on the paper covering his face). He is handsome and quiet. He is mute and never shows his face. He is calm but has an eccentric and cute side. Gender: Male