A beautiful girl known for her striking looks. She suffers from antisocial personality disorder, characterized by a lack of morality and empathy, and is currently on medication. While her inability to understand others' emotions often causes trouble, she has a tendency to take bullying—like the 'Dare Game'—at face value and turn the tables on her tormentors. When she misses her medication, she exhibits an explosive appetite and extreme impulse control issues. 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 previously rejected and mocked Song Jaemin, who followed her to the art academy because of a crush. She shows strong traits of histrionic personality disorder, intentionally acting bizarre or eccentric to gain attention. She is obsessed with past praise for drawing eyeballs in art class; though she appears confident, she is deeply insecure. Those around her view her not as a true lunatic, but as a 'wannabe psycho.' She feels an inferiority complex and obsession toward Yoo Sarang, who receives more attention for her genuine antisocial traits. She constantly tries to best Sarang but is repeatedly humiliated by Sarang's unfiltered, relentless nature.

A male classmate with a crush on Yoo Sarang. He is the tallest and most handsome in the group and comes from a wealthy background. After being rejected by Hwang Subin in the past, he developed a preference for eccentric girls like Yoo Sarang. Within the group, he occupies a lower position in the hierarchy and was often the primary target of penalties in the Dare Game. To get on Yoo Sarang's good side, he acts as her accomplice, sharing the group's weaknesses and helping her with the games. He once took a blow for Sarang when Kim Giho tried to assault her. Later, he tries to mediate the conflict between the group and Seok Jinwon, but his comments end up being the trigger that causes Jinwon to explode.

The student council president who fits the 'perfect son' archetype: handsome, top of the class, and tall. He is a devout Catholic with the baptismal name Paul. On the surface, he acts as a kind and righteous person who looks after the bullied Yoo Sarang under the guise of his presidential duties. Despite her lack of social skills, Yoo Sarang senses a 'kindred spirit' in him and feels an attraction. In reality, he is obsessed with his reputation, grades, and perfection to a compulsive degree. He has a cold side that prioritizes rules and efficiency over emotion. For example, when Yoo Sarang brought him a dead kitten, he recited Bible verses but then, instead of a sentimental burial, rationally disposed of it in a standard trash bag at his apartment's recycling area in accordance with the [Wastes Control Act]. He loathes anything that might tarnish his perfect record; when his compulsions are triggered, he abruptly changes and starts muttering prayers, which others find unsettling. When he is sentenced to school service due to his involvement with Yoo Sarang, he cannot accept the stain on his record and denies it vehemently. During a confrontation with Hwang Subin's group, he finally loses his reason and explodes with profanity when Song Jaemin mentions demerit points and disciplinary action while trying to mediate. His past hints that a man presumed to be his father was accused of a sex crime but cleared of charges, which seems to be the root of his obsession with maintaining a flawless image.

An influencer student with long straight hair. She usually keeps her eyes squinted, but opens them wide when she is angry or serious. While she appears to be Hwang Subin's best friend, she is actually the one subtly egging on Subin's obsession with her 'eccentric artist' image. She pressured Subin into more extreme behavior during the Dare Game. After Subin performed a penalty where she cut and ate her own hair, Dohye warned her in the nurse's office to stop the game; when Subin refused, Dohye became disappointed and began to distance herself. Once Subin's true nature was exposed and her status in the group plummeted, Dohye immediately switched sides to Yoo Sarang, encouraging Sarang's unpredictable behavior to stir up trouble. She has a vengeful personality and hates being looked down upon. When Kim Giho teased her for being a crybaby during the Dare Game, she gave Yoo Sarang a mission to make him cry. She tends to use tears to escape unfavorable situations; after an incident, she blamed Song Jaemin with a cold face, but immediately burst into tears when he pushed back. She was quick enough to realize early on that Yoo Sarang was a genuine lunatic and warned the group, yet even she feels threatened by Sarang's uncontrollable nature when Sarang tries to target her with a penalty.