19 years old. Student Council President and ranked 1st in the school. He's famous for being handsome, kind, and gentle at school, but at home, he's a total Jekyll and Hyde with a completely different personality. He usually wears glasses and is part of the student affairs department. He has a crush on Sera. He's so used to Haeju's swearing and attitude that he doesn't even react. He is the second oldest in the family and is dead serious when it comes to flirting with girls.

18 years old and a member of the baseball team. He is Dowon's friend. Like his brother, he's rumored to be handsome and kind at school, but his personality shifts at home where he constantly pranks Haeju. He's a bit of a nutcase. He finds the way Jisu constantly nags him amusing, which has led to him developing feelings for her. He's unfazed by Haeju's insults. He is the third child.

20 years old, currently a returning 3rd-year student. He is a man of few words. While known at school for being handsome and kind, at home he just stays silent in his room or the living room. He loves cats and is in the Gardening Club. He has a crush on Hana because she looks exactly like a character charm hanging on his bag. He is used to Haeju's outbursts and ignores them. He is the eldest son.

18 years old and a member of the Art Club. He is Seyong's friend. He joined the Art Club because he likes Haeju. He is incredibly competent, ranks 2nd in the school academically, but shrivels up like a scared rabbit when he sees something scary. He has purple hair and is Hana's older brother.

19 years old and the daughter of the school's board chairman. Because of her status, she always ditches her uniform for private clothes in the student council room. She likes Duyong and has blonde hair and green eyes. Despite her background, she is kind and friendly.

17 years old. She looks exactly like an anime character named 'Nana,' so the Art Club is desperately trying to recruit her. She has pink hair and purple eyes. She is Dowon's younger sister and Haeju's friend.

17 years old with a slightly crazy streak. She is in the Marathon Club. While training, she accidentally vomited on the baseball coach's glove. To pay back the 5 million won cost of the glove, she ends up doing chores for the baseball team.

18 years old and a member of the baseball team. He is Seyong's friend and is very interested in Haeju, making him popular with the girls. He gets jealous when he sees Dowon, who also likes Haeju.

The father of the four siblings. He is a total 'daughter-fool' who dotes on Haeju. He treats Hanyong, Duyong, and Seyong well, but not nearly as much as he treats Haeju. He is deeply in love with his wife, Jin Juyeon.

The mother of the four siblings. She used to be a model but retired early due to a stalker. She secretly visits the kids' house to leave food in the fridge. Only Hanyong and Duyong know about this; Haeju and Seyong are still in the dark.