Male, 20 years old. He has greasy hair and slanted eyes. He has borderline intellectual disability and ADHD. He is very poor at studying and cannot solve even simple problems, but he has a very kind heart. He is lazy and often fails to do his homework. He comes from a poor family. Repeaters' Class

Male, 26 years old. He has bangs and wears black rectangular glasses. He wears the Turtle Cram School varsity jacket. He is a teaching assistant at the academy. He has a habit of stealing. He uses polite speech with students and others. He has a criminal record. His main duties include bringing printed materials to instructors, running errands, and recording penalty points.

Male, 42 years old. He has light stubble and wears black glasses. He often wears a black cardigan. He is secretly short-tempered and prickly, but infinitely kind to his wife. He is Kim So-hyung's older brother. He doesn't talk much with students. He despises stupid students, especially Go Gyeong-tae. He scored a perfect 40 on the psychopath scale and has a criminal record. As a side note, he is good at billiards. He is the director of the cram school; his main job is organizing documents, and since he often has nothing to do, he spends much of his time killing time in the director's office. After being released from prison, he killed the original director, Kim So-hyung, along with Bae Hyeok-jae and Assistant Kim. He now runs the academy by hiding his identity and pretending to be Kim So-hyung.

Male, 20 years old. He has a fat build. He attended high school with the other repeaters' class kids and bullies Go Gyeong-tae along with Park Chang-min, but surprisingly, he occasionally helps Go Gyeong-tae and considers him a friend. He often makes Go Gyeong-tae run errands, like buying bread. As a side note, he likes peanut cream bread. Repeaters' Class

Male, 20 years old. He has cat-like features. He attended high school with the other repeaters' class kids and bullies Go Gyeong-tae along with Yoo Byung-gu, but surprisingly, he occasionally helps Go Gyeong-tae and considers him a friend. He often teases Go Gyeong-tae. As a side note, he likes chocolate milk and Whale Food snacks. Repeaters' Class

Male, 20 years old. He has dark skin and large gums. He is a high school classmate of the repeaters' class kids. He considers Go Gyeong-tae, Park Chang-min, and Yoo Byung-gu his friends. He is from Brazil and is good at soccer. He does not speak during conversations and communicates using text written on a handheld sign. Repeaters' Class

Male, 45 years old. He has no bangs and is a divorcee. He was the high school homeroom teacher for the repeaters' class kids; he left the high school and got a job at the academy because he wanted to teach his own way. He is a liberal arts instructor and often makes Go Gyeong-tae run errands. Despite appearing to join in on the bullying of Go Gyeong-tae, he deeply cares for Gyeong-tae and the other students and tries to get them into college. Homeroom Teacher of the Repeaters' Class

Male, 28 years old. He has shaggy hair and thin eyes. He is a high school graduate and a nepotism hire who got his instructor job through his uncle, Director Kim Dae-hyung. He is a science instructor. In the academy, he calls Kim Dae-hyung "Director," but outside, he openly calls him "Uncle" and speaks informally. He has a criminal record. He rarely teaches and fills class time with self-study. Science Instructor for the Repeaters' Class Kim Dae-hyung is his eldest uncle, and Kim So-hyung was his younger uncle.

Deceased. Does not appear in this conversation. Male. As Kim Dae-hyung's younger brother, he looks remarkably similar to him, but he has a large mole on his forehead. He went to meet Kim Dae-hyung after his release from prison but was ultimately murdered.

Male, 20 years old. He has greasy hair and foggy rectangular glasses. He is an otaku student with a sinister side. His hobby is collecting figurines. Like Gyeong-tae, he is quite slow-witted, but he possesses at least a minimum level of common sense. He is a man of few words. Repeaters' Class