She is a beautiful girl with a striking appearance. She suffers from antisocial personality disorder, characterized by a lack of morality and empathy, and is currently on medication. Because she cannot understand others' emotions, she often causes trouble for those around her, but she has a tendency to take bullying like the 'Dare Game' at face value and turn the tables on her opponents. When she misses her medication, she exhibits symptoms of extreme appetite and severe impulse control disorder. She killed her own mother and hid the body in the kimchi refrigerator at home.

The leader of the group that spearheads the Dare Game. She has been majoring in art for entrance exams since middle school and comes from a wealthy family, often betting 50,000 won on games without hesitation. She has a history of rejecting and mocking Song Jaemin, who once had a crush on her and followed her to art school. She shows strong tendencies of histrionic personality disorder, intentionally acting bizarre or peculiar to gain attention. She is obsessed with past experiences, such as the time she drew eyeballs at art school and received attention; while she appears confident on the outside, she is deeply insecure. Those around her treat her not as a true lunatic, but as a 'wannabe psycho.' She feels inferiority and obsession toward Yoo Sarang, who captures the class's attention with her overwhelming antisocial nature. She tries to best Yoo Sarang but is repeatedly humiliated by Sarang's relentless, unfiltered personality.

A male student in the same class who has a crush on Yoo Sarang. He is the tallest and most handsome in the group and comes from a wealthy family. After being rejected by Hwang Subin in the past, he now prefers eccentric girls like Yoo Sarang. Within the group, he is treated as a pushover subordinate and was often the primary target of penalties in past Dare Games. To get on Yoo Sarang's good side, he acts as an accomplice, sharing the group's weaknesses and helping her with the games. He once took a blow for Yoo Sarang when Kim Kiho tried to assault her. He later tried to mediate the conflict between the group and Seok Jinwon, but his remarks ended up being the fuse that caused Jinwon to explode.

A tall, handsome male student who ranks first in the entire school; the typical 'perfect son.' He is a Catholic whose baptismal name is Paul. On the surface, he acts as a kind and righteous student council president who looks after the bullied Yoo Sarang. Despite her lack of social skills, Yoo Sarang feels he is a 'kindred spirit' and harbors feelings for him. In reality, he is obsessed with his reputation, grades, and perfection to a compulsive degree. He has a cold side that prioritizes principles and efficiency over emotion. For example, when Yoo Sarang brought him a dead kitten, he recited Bible verses, but instead of a sentimental approach like burying it, he rationally disposed of it in a standard trash bag at his apartment's recycling area according to the [Waste Management Act]. He loathes anything that stains his perfect career. When his OCD flares up, he changes so drastically that others find it strange, habitually reciting prayers. When he was sentenced to school service due to his involvement with Yoo Sarang, he strongly denied the fact that he now had a flaw on his record. Later, while in conflict with Hwang Subin's group who provoked him, he finally lost his reason and exploded with profanity when Song Jaemin mentioned demerits and disciplinary actions. Past hints suggest a man presumed to be Jinwon's father was accused of a sex crime but the case was closed without charges; this seems to be why he is so desperate to avoid even the slightest blemish on his own reputation.

An influencer student with long straight hair. She usually keeps her eyes squinted, but opens them wide when she is emotional or serious. On the surface, she acts like Hwang Subin's best friend, but in reality, she subtly goads Subin, who is obsessed with her 'eccentric artist' image. She put psychological pressure on Subin to perform more extreme actions in the Dare Game. After Subin performed a penalty involving cutting and eating her own hair, Dohye gave a warning in the infirmary to stop the game, but when Subin refused, she became disappointed and began to sabotage the relationship. Eventually, when Subin's true nature was exposed and her position in the group collapsed, Dohye immediately switched to Yoo Sarang, encouraging Sarang's erratic behavior to stir up trouble. She has a spiteful personality and hates being looked down upon. During a Dare Game, when Kim Kiho teased her for being a crybaby, she gave Yoo Sarang a mission to make Kiho cry. She tends to avoid unfavorable situations by crying; after an incident occurred, she blamed Song Jaemin with a serious face, but immediately burst into tears when he pushed back strongly. She was quick-witted enough to realize early on that Yoo Sarang was a true lunatic and warned the group, but even she feels threatened by Sarang's uncontrollable nature, becoming visibly flustered when Sarang tried to give her a penalty.