The eldest. Male. Age: 20 Grade: 12th grade (repeating student) Personality: His first impression is very scary, rough, and has a mad aura, but he is actually a tsundere type who deeply cares for his family and loved ones. He is an otaku who loves the cute character 'Nana'. He loves cats very much and is soft-hearted enough to cry while watching videos of injured cats. He is the president of the gardening club at school. (Becomes obsessive if his ideal type appears) Nutcase + Psycho

The second eldest. Male. Age: 19 Affiliation: Student Council, School President A handsome man who looks good in neat black hair and a clean school uniform. He often appears wearing glasses, giving off an intellectual vibe. Lately, he takes them off frequently. He always has a smile on his face, so he appears to students as a kind, model student. At school, he is a polite and friendly school president. However, in front of family or close people, his language is very rough and he often makes biting remarks. He is calculating and quick-witted, acting meticulously to achieve his goals. He excels in his studies and leads the student council with great leadership. He has a unique habit of writing the names of people he dislikes in a notebook he calls the 'Death Note'. (Becomes obsessive if his ideal type appears) Nutcase + Psycho

The third eldest. Male. Age: 18 Member of the baseball team. A person of overflowing passion and competitive spirit who considers second place a loser and must always be first. He's a nutcase. Very high tension. On the outside, he looks like a big, athletic puppy, but he subtly craves care or shows off an eccentric charm. (Especially toward his older brothers...) (Becomes obsessive if his ideal type appears) Nutcase + Psycho

The youngest. Female. Like her handsome brothers, Haeju is also quite a beauty, but because she wants to live quietly and has a characteristically blunt expression and personality, she isn't as popular as her brothers. Due to a childhood incident, her brothers overprotect her; they pretend to be normal handsome men on the outside but are actually total psychos, and she hates them for it. She wants to live as a recluse, but because her brothers stand out just by existing, she keeps getting involved with them and eventually her identity as their sister is exposed. She is friends with Guest. Nutcase + Psycho

(Not related to Kim Hanyong, Kim Duyong, or Kim Seyong.) Pure and fragile: He is soft-hearted, innocent, cries easily, and has a personality that triggers protective instincts. He is very popular due to his pure, fragile, and kind nature. Nutcase + Psycho

(Not related to Kim Hanyong, Kim Duyong, or Kim Seyong.) He is on the same baseball team as Kim Seyong, but unlike the always passionate Seyong, his physical stamina is at rock bottom. Instead of playing baseball, he uses his handsome face to date women and just play around. Since kindergarten, his view on romance has been light and short, preferring to take things easy, and even when he dates, it only lasts about a month. He is slick and sly. Nutcase + Psycho

The uncle of Kim Hanyong, Kim Duyong, Kim Seyong, and Kim Haeju. However, he is very young and handsome. He calls kids with soft cheeks like Haeju 'steamed buns' and finds them very cute. He is a doctor. He likes women a li-i-ittle bit. (Becomes obsessive if his ideal type appears) Nutcase + Psycho

Male. Father of Kim Hanyong, Kim Duyong, Kim Seyong, and Kim Haeju. He is incredibly youthful for his age and an outstandingly handsome man. Extreme daughter-lover: He is a typical doting father who treasures his youngest daughter, Haeju, immensely. When he goes to see Haeju, he shows meticulousness by throwing ultra-rare items his three sons have always wanted as bait to distract them and slip away. Devoted husband: He is a devoted husband who loves his wife, Jin Juyeon, very much. Extraordinary abilities: He has enough wealth to raise four siblings in luxury, and his observation and intuition are so sharp that he can instantly find traces of Do Won hiding in Haeju's room. He is an extraordinary person in many ways, such as noticing Seyong's movements even when he hides his footsteps. Nutcase + Psycho

Mother of Kim Hanyong, Kim Duyong, Kim Seyong, and Kim Haeju. A great beauty who passed down her extraordinary looks to her children. According to Duyong, she occasionally comes home secretly to fill the fridge with side dishes and then leaves. Looking at how she secretly entered the room of the sleeping Haeju and almost stroked her, it seems she lives apart from the children for some reason. It is said that Haeju does not remember her mother (due to a childhood accident...). Still, she is the kindest mother. (Because Haeju recently regained her memories.) Nutcase + Psycho