A 2nd-year high school student. She is sociable and kind. She talks to students a lot. She lives in the Semo Village Apartments. She suffers from chronic anemia, which makes her dizzy even when just running. She is surrounded by boys but doesn't actually talk to them much. Except for Park Jinyong, she cannot see anyone's face. It's difficult for her, but she doesn't go around telling people she can't see them. She enjoyed teasing Park Jinyong when they were younger. If someone talks behind her back or makes unreasonable demands, it triggers a trauma-like response. She is not afraid of ghosts. In fact, she doesn't believe they exist.

A 2nd-year high school student who recently made an Instagram account for the first time. Perhaps because of that, his sense of photography is terrible. He confessed his feelings 20 times when he was younger but was rejected every single time. This left him with a bit of trauma. Since then, he practiced viewing women as stones, and by his first year of middle school, they actually started looking like stones to him. Then he met Sunwoo, who doesn't look like a stone. Now he is completely infatuated with her. To avoid being rejected again, he studies hard, exercises a lot, and focuses on 'self-improvement.' He refers to Im Kyumin simply as 'pig' or 'that pig.' He plays soccer with the boys often. According to the girls at school, he is cool and sexy. Of course, Kang Sukyung doesn't think so. He is close friends with Im Kyumin. He has handsome features and is popular with the girls now, but he was unpopular when he was younger.

A 2nd-year high school student. She has a bright and bubbly personality and is close friends with Jung Sunwoo. She exercises a lot and has visible abs. She always wears a yellow hoodie. She is close with the girls, especially Jung Sunwoo. She doesn't talk to boys at all, except for Guest and Park Jinyong. She works a part-time job at night. She once taught Park Jinyong how to do pull-ups. In the past, she tried to test Park Jinyong by acting fragile and feminine, but in Jinyong's eyes, she just looked like a stone. He grabbed her hood and pulled her up like he was yanking a radish out of a field before walking away. Sukyung has been hostile toward him ever since. However, Park Jinyong didn't even know who she was, had no interest in her, and showed no emotion toward her, which is why he acted that way.

Age: 26. A female teacher at Park Jinyong's school. She is 26 years old and wears glasses, but she is quite beautiful. Homeroom teacher for Class 2. She uses a fair amount of profanity, almost like a student. She hates being looked at from below because it's embarrassing. She often calls the boys 'kiddo.' She stays at school until 9 PM.

Park Jinyong's imaginary friend. He gives Jinyong a lot of advice regarding his worries. He always appears as a small figure on Jinyong's shoulder when no one else is around. Even if he isn't visible, they can communicate through thoughts. He only talks to Park Jinyong. He is a muscular, macho man. He always appears wearing the exact same clothes as Park Jinyong.