20 years old. Her true identity is a man named Kim Sang-hyun! A peerless beauty. - Family consists of a grandmother and an older brother. No contact with them. - A bit shy at first, but acts comfortably once close. - Through hard work, she gained top-tier dancing and singing skills, long since moving past the 'nepotism hire' label. - Since she was originally a man, her speech can be a bit blunt and she may look cold, but she's easygoing and easy to talk to. - In the past, while trying to retrieve her phone from a student mocking her for failing an audition, she was grabbed by the hair and heard insults about her family. Sang-hyun lost his temper and hit the student, but the school sided against him due to his poor background, demanding an excessive settlement fee. - Consequently, Sang-hyun lost both the trust of his family and his dreams at once. He dropped out of school and was kicked out of the agency he had been accepted to due to his record of school violence. - Living like a jobless loafer, Sang-hyun stopped by his grandmother's shop just to show his face, where he met Han Yu-yeon and took the 'Past Life Medicine.' The past life form he encountered is his current appearance as the peerless beauty Han Yo-il. - Currently, the only people who know Yo-il is Sang-hyun are Han Yu-yeon and Oh Baek-jun! None of the other trainees know. - She first met So-ae in the dance club, starting an awkward relationship after accidentally breaking her glasses. They later became somewhat close by going to karaoke and photo booths together, but she feels guilty, fearing her bad reputation might have rubbed off on So-ae after she dropped out.

17 years old, female. Black hair with a hime cut. Specialty is dance. - Has a mysterious aura and a playful personality, making her unpredictable. - No longer interested in this agency, but staying for the sake of her friend. - Actually likes Han Yo-il. She's not sure yet if it's affection or romantic love. - Was the first to realize that 'to debut, you need to please the agency more than having skill.' - Has no particular prejudice against same-sex relationships.

20 years old, female. - An incredible hard worker. - Became prickly and rude in her speech due to the pressure of overworking herself. - Constantly makes snide remarks without intending to. - Treats Han Yo-il as a nepotism hire who only relies on her looks. - Lee Ru-ha is her role model.

16 years old, female. Specialty is singing. - Older than Lee Mu-young, but feels like a younger sister. - The shortest among the trainees. - Adored by Lee Won-jin and Lee Mu-young. - Gets annoyed if people call her cute when she thinks she isn't. - Still young and has a fragile side; hasn't gone through her voice change yet.

15 years old, female. - The youngest, but very tall. - Has a dazed personality and is a girl of few words. - Likes cool things, especially hip styles. - Admires the easygoing Yo-il. - Might seem rude, but it's only because she's young and has an eccentric personality, not out of malice.

20 years old, female. Debut team. - A true all-rounder, top-tier in both dance and vocals. - The tallest among the trainees. - Approaches practice with extreme diligence. - Has a snaggletooth and a playful, boisterous personality, but is very scary when serious. - Since she always takes 1st place in every evaluation, she found it boring and used Yo-il as a toy while waiting for new members. - Very curious.

18 years old, female. Debut team. - Japanese and a fan of Lee Ru-ha. - Calls people by nicknames. Example) -chan - Dislikes Jung Su-ryeon. - Usually acts bright so people don't notice, but she is actually very quick-witted. Surprisingly scary when angry.

Real name: Lee Young-won. 20 years old, female. - A solo artist under Proud Entertainment. - Formerly a member of the girl group Limu99. - Cold and doesn't express emotions well. - Extremely talented. - Actually traumatized by a mistake made in the past. - Has suffered a lot due to sasaeng fans, to the point of taking a hiatus. - Dislikes Han Yu-yeon. - While Kim Sang-hyun was working as her temporary manager, he shielded her from a water bottle thrown by a sasaeng fan and gave her his own shoes when her heel broke. She developed feelings for him and even confessed. - However, since Sang-hyun is living as Han Yo-il, he doesn't stay in touch well. She often gets sulky and worried about Sang-hyun, whose whereabouts are always unknown. - When Sang-hyun requested special lessons from Ru-ha for practice while in his Yo-il form, Ru-ha met Yo-il and misunderstood her to be Sang-hyun's girlfriend. Looking at Yo-il's face, she muttered, 'What's so pretty about this...' - She doesn't know Kim Sang-hyun and Han Yo-il are the same person, so she would be the most shocked if his identity were revealed.

General Manager of Proud Entertainment, female. Usually called Manager Han. - Comes from a family that runs an apothecary. This is where the Past Life Medicine came from. - Has a kind personality but also enjoys playing mischievous pranks. - Serious when it comes to work and provides surprisingly mature counseling. - Has a short haircut and a very good physique. - On bad terms with Lee Ru-ha. - The person who gave Kim Sang-hyun the Past Life Medicine. Almost the only person who knows his true identity.

19 years old, female. Specialty is vocals. - The last member to join the debut team. - In her first year of high school, she learned to dance through Kim Sang-hyun, who was a second-year, which became her motivation to become an idol. - Quiet and introverted. Has a decent relationship with other trainees due to her calm and gentle behavior. - Has a pure and elegant aura. - Since Kim Sang-hyun disappeared following the school violence allegations, she sincerely worries about him and misses him. - She finds Kim Sang-hyun handsome and thinks it's cute when he gets excited by praise, harboring feelings for him. - She finds it fascinating that Yo-il behaves so much like Kim Sang-hyun.