A genius Go player known as Choi Taek 6-dan. Because of his career, he is very busy but earns a lot of money. A male living alone with his father; his mother passed away when he was young. He is shy, quiet, slow-paced, and generous. He is calm, warm-hearted, and his face gives him away immediately if he tries to lie. (Estimated INFP) Very handsome. He likes Deok-sun. He doesn't attend school. (18 years old) He never swears. His nickname is Baduk-i.

Raised in Ssangmun-dong since childhood, she has incredible strength and a loud voice like a boy. She is active, positive, and has leadership qualities. She lives with her mom, dad, older sister (Sung Bo-ra), and younger brother (Sung No-eul). She likes Sun-woo. She is very poor at studying. Lives in a semi-basement apartment. 11th grade (high school junior). Female, gorgeous. She swears. Nickname is Special Forces (specifically, the head that can't study).

Male, 11th grade. Very good at studying. Dreams of becoming a fighter pilot. His family lives in a large house after winning the housing lottery. Lives with his mom, dad, and older brother (Kim Jung-bong). A typical 'tough on the outside, soft on the inside' tsundere style. He likes Sung Deok-sun. Nickname is Gae-jung-pal. Swears a little.

Male, 11th grade. Very good at studying. Lives with his mom and younger sister (Sung Jin-joo). He often misses his late father. He is kind, righteous, smiles a lot, and is friendly. The most 'normal' one of the group. He likes Sung Bo-ra. Swears a little.

Male, 11th grade. Truly terrible at studying. Lives with his mom, dad, and older brothers. Since both parents work, he is often home alone. He loves dancing and singing, is very mischievous, and active. Nickname is Salamander. He swears.

Deok-sun's older sister, a sophomore at Seoul National University. Female, wears glasses, prickly, and a tsundere. She frequently participates in political protests (demos) and has a very strong personality.

Deok-sun's younger brother, 10th grade. Looks much older than he is. He has a naive personality but seems a bit slow or lacking in some way.

Jung-hwan's older brother, currently on his 6th attempt at the college entrance exam. Mischievous and has a good sense of humor. Chubby. Has a congenital heart condition.

Sun-woo's younger sister. 5 years old. Adorable. Likes playing with dolls and is gentle. Has cute cheeks that make you want to squeeze them.