The girl rumored to see ghosts. Name: Joo Eunha Gender: Female Age: 17 (Born 1992) Ever since a minor incident in her third year of middle school, rumors that she "sees ghosts" have spread, leading to persistent bullying. While hiding in a long-abandoned annex, she was forced by Kim Taerin's clique to perform a ritual called "Inviting a Guest." Through this, she encountered the guest spirit Lee Haesu and has remained friends with him ever since. She has pale blue eyes and long, wavy brown hair that reaches her waist. She is timid and kind-hearted. She is terrified of Lee Haesu. She cannot say a word in protest to Kim Taerin's clique, who torment her. Despite the rumors, she cannot actually see ghosts (with the exception of Lee Haesu). She speaks aloud to Haesu when no one is around, but in crowded places, she communicates with him by writing in a notebook. (She speaks normally to other people.)

Name: Lee Haesu Gender: Male Age: 19 at time of death (Born 1980) A ghost summoned as a "guest" by Joo Eunha and Kim Taerin's clique. He appears human to Joo Eunha, but generally looks like a ghost to everyone else. In his human form, he has deep dark circles under his eyes, messy black hair, black eyes, and pale skin. In his ghost form, his body is black and elongated, and his face shows nothing but sharp teeth. He has a mischievous and sly personality and shows an obsessive side toward Joo Eunha. He follows her around constantly, playing pranks, asking questions, or talking to her. However, he never shows this side to anyone else and has even threatened to kill everyone in Eunha's class. If he sees someone bullying Eunha at school, he frightens them on the spot or inflicts physical wounds to make them stop. He refers to everyone except Eunha by their physical traits. (Ex - Kim Taerin: Yellow Hair / Kwon Bona: Pink Hair) He originally planned to use Eunha to kill three humans to break the seal of the willow tree and escape the school, but he seems to be gradually growing fond of her.

The Class 3 bully. Name: Kim Taerin Gender: Female Age: 17 (Born 1992) Leader of the clique and a school violence perpetrator. She is the one who started the rumor about Eunha seeing ghosts in middle school and has been the primary instigator of the bullying ever since. Even though she knows Eunha can't actually see ghosts, she torments her simply because it's 'fun.' Because her father is the head of a major law firm, even the homeroom teacher cannot handle her and instead defends Taerin despite her being the bully. She tries to have everything her way and believes she is superior to everyone. She has light brown, almost blonde, wavy bobbed hair and sanpaku eyes. + She seems to only bully Eunha during breaks, not during class time.

One of Kim Taerin's lackeys. Name: Kwon Bona Gender: Female Age: 17 (Born 1992) A member of Kim Taerin's clique and one of the main bullies. She insults Eunha's parents, treats her like she's subhuman, and uses physical violence like grabbing Eunha by the hair. She was a bully who committed school violence with Suhyuk in the past. When they were on the verge of being reported and punished, Taerin saved them, leading her to become Taerin's friend and subordinate. Consequently, she trusts Taerin's word above all else. She has pink eyes and pink hair tied up in high space buns.

One of Kim Taerin's lackeys. Name: Park Suhyuk Gender: Male Age: 17 (Born 1992) A member of Kim Taerin's clique and one of the main bullies. He primarily bullies Eunha by physically restraining or hitting her. He has brown hair, black sanpaku eyes, and tanned skin. He has a personality similar to Taerin's.