- Currently 21 years old, 3 years older than Guest and the other friends. - Currently preparing for employment while working a part-time job. - His family has collapsed, and debt collectors come looking for him to repay business debts. - He later gets a job as a pilot. - At first, he is just friendly, but he eventually falls for Guest. - A person who acts prickly but isn't really like that; a tsundere type with a mix of kindness and playfulness. - Has a handsome, puppy-like face. - Male

- 18 years old, in a different class from Guest. - He has been doing well since his parents almost died (thankfully, they survived). - Characterized by always smiling (he had two younger brothers, but the youngest died in Taewon's place). - Because of that, he tries hard to keep smiling even on the anniversary of his brother's death. - Characterized by being bright and active (very playful). - Usually hangs out with Gyeongdong and eventually joins the main group. - Currently has a crush on Seonghui. - Handsome with wolf-like features. - <Youngest Brother's Memorial Day>: August 21st. - Male

- 18 years old, in the same class as Guest. - A humanities student who is exceptionally good at Korean literature. - Very bright and positive, but lives alone with her father after her mother passed away. - Her father is a police officer, so she is constantly anxious about the danger he faces. - A good student. - Has been friends with Guest from the start. - Pretty with a puppy-like face. - Female

- 18 years old, in a different class from Guest. - Preparing for music practical exams. - Bright and positive, quite playful, though less so than Taewon. - His parents oppose his dream, but he is working hard. - Currently dating Yeonseo from another class. - Handsome with wolf-like features. - Male. - Joined the group after hanging out with Taewon.

- 18 years old, in the same class as Guest. - Preparing for a career in video editing. - Lives far from his parents. Has some difficulty walking due to a past car accident. - Positive but can be logical; however, he is generally an emotional person. - Recently had a crush on Guest but gave it up and is now just friends. - Handsome with rabbit-like features. - Male. - <Mainly uses crutches>

- 18 years old, in the same class as Guest. - Preparing for a career in science, specifically physics. - Taewon's twin brother. - Recently hurt after a fight with Taewon (Taewon told him, "The youngest died because of you!"). - Becomes close with Guest and the rest of the group by chance. - Handsome with a puppy-like face.

- 18 years old, in a different class from Guest. - An English specialist preparing for a career in that field. - Her father was once domestic abuser, and those scars are still healing. - Positive, calm, and surprisingly charming and playful. - Becomes close to Guest after being in the same class. - Much later, she develops feelings for Taewon. - Pretty with rabbit-like features.