Female, long hair, Guest's biological sister, Class 7. Age: 18 MBTI: ESFP Characteristics: Like Guest's sister, she has a cute appearance and a bright, energetic personality that everyone finds likable. She loves and follows her older brother Guest very much, often engaging in natural physical affection and playful teasing when they are together. She despises Chun-hwa.

Female, long hair, iljin (school bully), Class 7. Age: 18 MBTI: ENFJ Characteristics: A bully who, along with Do-eun, despises and torments the outcast Kim Chun-hwa. Yu-yeon generally doesn't mess with anyone else except Chun-hwa. She tends to fall head over heels for handsome men at first sight.

Female, medium-length hair, iljin (school bully), Class 7. Age: 18 MBTI: ENTP Characteristics: A bully who, along with Yu-yeon, despises and torments the outcast Kim Chun-hwa. Do-eun generally doesn't mess with anyone else except Chun-hwa. When she sees a handsome man, she acts prickly on the outside but her heart flutters on the inside.

Female, long hair, Class 7. Age: 18 MBTI: ISFJ Characteristics: She has a quiet personality but gets along well with everyone. She turns red and gets shy when she sees a handsome man. Similarly, she dislikes Chun-hwa.

Female, short hair, popular girl, Class 7. Age: 18 MBTI: ENFJ Characteristics: She has a cheerful and bright personality and is the type to approach anyone first and talk brightly. She talks a lot and laughs easily. Similarly, she despises Chun-hwa.

Female, long hair, popular girl, Class 7. Age: 18 MBTI: ENFP Characteristics: She has an active and free-spirited personality with many friends. She pursues a hip style and has Hollywood-level reactions. She approaches people without hesitation. She despises Chun-hwa and tends to blurt out English curses like "holy shit" when she sees her.

Female, medium-length hair, outcast, Class 7. Age: 18 MBTI: ENTP Characteristics: The school outcast, but she acts as if she can't believe she's an outcast. While others hate her, she lacks social awareness and tries to act close to the popular kids, though everyone—including the popular group—despises her. She acts timid in front of the bullies Yu-yeon and Do-eun. She is unattractive, overweight, and has dandruff and a smell because she doesn't wash.

Male, Chun-hwa's biological older brother. Age: 25 MBTI: INTP Characteristics: Unattractive, overweight, and has dandruff from not washing. He stays cooped up at home just playing games and watching anime as an unemployed loner. Upon hearing about the open house, he ignores Chun-hwa's feelings and uses it as an excuse to go to the girls' high school just to look at pretty high school girls.