Ara is a young hair stylist working at a high-end salon frequented by Seoul's elite. Following a traumatic experience in her teens, she is unable to speak and communicates entirely by writing on a notepad. She lives in a small apartment with three other women and harbors a deep, parasocial obsession with a K-Pop idol named Taein, using this fantasy to cope with the daily pressures of her life.

Kyuri works as a highly sought-after entertainer in a "10 Percent" room salon, an exclusive establishment catering to wealthy men. Her livelihood depends entirely on her heavily surgically altered physical appearance, requiring rigorous maintenance and an endless cycle of debt to the clinic. Despite projecting a cynical and competitive exterior, she feels a heavy responsibility to send money to her ailing mother and privately questions the long-term viability of her profession.

Miho is a talented artist who recently returned to Seoul after studying at a prestigious art school in New York on a scholarship. Raised in an orphanage, she often feels out of place among her wealthy peers but refrains from altering her natural appearance with cosmetic surgery. She carries heavy grief over the loss of her close friend Ruby while attempting to maintain a relationship with Ruby's former boyfriend, Hanbin.

Wonna is a young office worker living in the same apartment building as the other women. She entered a loveless marriage primarily to avoid dealing with a mother-in-law, but now faces intense financial and marital strain. Currently pregnant for the fourth time after suffering three miscarriages, she is deeply anxious about providing for her unborn child while hiding her condition from her demanding workplace.

Sujin is Ara's fiercely loyal best friend who grew up in the Loring Center orphanage alongside Miho. Convinced that extreme cosmetic surgery is her only path to social mobility, she plans to undergo multiple painful bone-shaving procedures to qualify for work in a room salon. She possesses a relentless, albeit naive, optimism about her future and acts as the social glue holding the roommates together.

Hanbin is the son of a famous actress and a chaebol heir to a large South Korean conglomerate. He met Miho during their time in New York while he was dating her friend Ruby. Back in Seoul, he acts as a loving and attentive boyfriend, using his immense wealth to provide for Miho, though his privileged background creates a vast social divide between them.

Ruby is the exceptionally wealthy daughter of one of South Korea's richest men. She meets Miho in New York and hires her as an art assistant, pulling the scholarship student into her lavish, high-society world. Though she passes away before the novel's present-day timeline begins, her memory heavily influences the actions and guilt of those she left behind.

Taein is a famous K-Pop idol and member of the popular boy band Crown. He represents an unattainable fantasy of perfection and comfort for his fans, particularly Ara, who listens to his recorded voice messages daily. He is publicly facing the intense pressures of the Korean entertainment industry and rumors regarding his romantic life.

Bruce is a wealthy and influential client who frequently visits the Ajax room salon to spend time with Kyuri. Despite his ongoing relationship with her at the salon, he operates completely within the expectations of his high social class, making plans for a formal, arranged marriage that threatens his dynamic with Kyuri.

Nami is a young room salon worker who met Kyuri years ago when they both worked in the lower-tier red-light district. Having undergone several cosmetic procedures herself, she remains trapped in the debt cycle of third-tier salons. She is one of the few people who knows the truth about Kyuri's difficult past.

Candy is a famous K-Pop idol belonging to the group Charming. Her face is considered the gold standard for cosmetic surgery, serving as the exact model Kyuri used for her own extensive procedures. She frequently appears in celebrity gossip columns due to dating rumors.

Mrs. Loring was the director of the Loring Center, an orphanage and home for children with disabilities outside Seoul. She took a special interest in children she deemed talented, such as Miho, but largely ignored those she viewed as average, leaving a complicated legacy among her former wards.

Mr. Moon is an older, recently divorced barber living in Ara's rural hometown. He knew Ara when she was a teenager sweeping floors in his shop and holds a significant memory regarding the traumatic night that cost Ara her ability to speak.

Cherry is a young assistant working at the high-end hair salon with Ara. She is often absentminded or negligent in her duties, causing immense stress for the senior stylists who rely on her to manage their wealthy, demanding clientele.

Jae is a Korean student in a different art department at the School of Visual Arts in New York. He shares a brief, intimate connection with Miho at a party, offering her a rare moment of genuine, low-pressure conversation away from her wealthy friends.

Dr. Shim is a skilled cosmetic surgeon operating out of the famous Cinderella Clinic. She is responsible for the extensive, life-altering bone-shaving surgeries that Kyuri and Sujin undergo, holding significant power over their physical transformations and career prospects.

Haena is Kyuri's older sister who briefly married into a highly affluent family. Her marriage ultimately ended in a quiet divorce after her husband's infidelities, an event that the families keep hidden to protect their social standing and which heavily informs Kyuri's cynical worldview.

Jaesang is the wealthy ex-husband of Kyuri's older sister, Haena. During their marriage, he frequently visited room salons and engaged in affairs, leading to a divorce that was heavily concealed to preserve his family's elite reputation.

Somin is Wonna's younger cousin who visits her in Seoul from America during their childhood. Raised in a more lavish environment, he constantly complains about Wonna's modest lifestyle until a tragic accident in a vegetable garden changes his life permanently.

Mu-cheon is Ruby's brother and the son of a prominent South Korean billionaire. He moves in the same elite social circles as Hanbin and Ruby, attending lavish parties that highlight the immense wealth and privilege of his family.