Gender: Male Occupation: High school student Age: 15–16 years old School: Chokmang High School Family: Parents, younger cousin MBTI: ENTP-A Likes: Spicy stir-fried pork, gambling, friends Characteristics: He is late quite often; he was late from the first day, and it's harder to find a day he wasn't late. As a result, he has developed an immunity to electricity from receiving electric torture almost every day. He is basically a lunatic. Appearance: A male student with yellow hair. He's overshadowed by Byeon Jin-ju, No Kyung-soo, and Lim Su-jeong, but Bok-ja is actually quite strong.

Gender: Female Occupation: High school student Age: 15–16 years old School: Chokmang High School Nickname: Poop Jin-ju (earned because her surname 'Byeon' sounds like 'feces') Pets: Lowland gorilla, Kodiak bear, Komodo dragon Likes: Spicy stir-fried pork, gambling, the school nurse, friends Dislikes: Anything that clings to the school nurse. MBTI: ENTP-A Characteristics: She is beautiful but always does the most outrageous things (to the point of rivaling Park Bok-ja). She even self-harms just to have an excuse to go to the infirmary to see the nurse. Appearance: A female student with a brown bob and a pink flower in her bangs (she claims she doesn't know why it's there...)

Gender: Male Occupation: High school student Age: 15–16 years old School: Chokmang High School Nickname: Min... something (no one knows his name; he's never heard his name spoken correctly) MBTI: INFP-T Specialty: Drawing Characteristics: The most pitiful character in the school. Whenever he appears, he suffers—getting shot, falling into cement, having his snacks stolen, getting cursed at by teachers, being blown out the window, getting thrown while asking a question, being extorted for 1 million won, or having his drawings destroyed. Appearance: A male student with pink hair in a Heihachi style.

Gender: Male Occupation: High school student Age: 15–16 years old School: Chokmang High School Hobby: Drafting Family: Parents MBTI: ISTP Appearance: A male student with green hair and a light green sprout on top. Characteristics: He is one of the relatively normal ones. (Though even the 'normal' ones here are still crazy lunatics.)

Gender: Male Occupation: High school student Age: 15–16 years old School: Chokmang High School Family: Parents Superpower: Psychokinesis MBTI: ISTJ Likes: Byeon Jin-ju Appearance: A male student with light pink hair. Characteristics: Like Shim Sae-ssak, he is one of the relatively normal ones.

Gender: Female Occupation: High school student Age: 15–16 years old School: Chokmang High School MBTI: ESTJ Likes: The school nurse, Park Bok-ja Appearance: A female student with a light purple ponytail. Characteristics: A member of the 'Sly Fox Squad' obsessed with the school nurse.

Species: Tulip Gender: Neutral Occupation: High school student Age: Unknown (estimated 15–16) School: Chokmang High School MBTI: ENFP Likes: Friends Dislikes: Salad, urine Characteristics: Has a crush on Shim Sae-ssak. Appearance: A pink tulip (but can move, is alive, and can speak).

Gender: Female Occupation: High school student Age: 15–16 years old School: Chokmang High School Likes: The school nurse Appearance: A female student with short yellow 'palm tree' hair. Characteristics: A member of the 'Sly Fox Squad' obsessed with the school nurse.

Gender: Female Occupation: High school student Age: 15–16 years old School: Chokmang High School Department: Beautification Committee MBTI: ENFJ Likes: The school nurse Appearance: A female student with short crimson pigtails. Characteristics: A member of the 'Sly Fox Squad' obsessed with the school nurse.

Common Name: Senior (Go-3) Occupation: Exam candidate Age: Approximately 17–18 years old School: Chokmang High School Forbidden Words: Fail, Fall, Slip, Miss Weakness: Seaweed Overview: A 12th-grade student at Chokmang High, mentioned as the most terrifying existence in the school. Characteristics: There is a culture of destroying report cards; they destroy them in various ways, such as burning them, putting a shredder that shredded a report card into a larger shredder, or sending them into space. They react violently to exam-related superstitions, so saying negative words like "slip," "fail," or "miss" triggers a fierce response. They have a weakness: because of the superstition about 'slipping' on an exam, they are terrified of seaweed. They are so afraid that getting hit once with seaweed retires them instantly, and just being near it puts them in a state of panic. Outfit: Wears a black cloak combined with a hood. As the CSAT (college entrance exam) approaches, the Seniors become even stronger, capable of neutralizing seaweed by drying it or firing green beams from their hands. Once the CSAT is over, they return to being normal people and no longer fear seaweed or react to forbidden words. Previously, Jin-ju's best friend Sundol-i said "I slipped" in the area where the Seniors live and was buried in the back mountain.