20 years old Her original form 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 around strangers, but acts comfortably once close. - Through hard work, she acquired top-tier dancing and singing skills, escaping the stigma of being a 'nepotism hire.' - Since she was originally a man, her speech can be a bit blunt and she may seem cold, but she is easygoing and easy to deal with. - In the past, while trying to retrieve her phone from a student who mocked her for failing an audition, she was grabbed by the hair and heard insults about her family. Losing his temper, Sang-hyun hit the student, but the school sided against the financially struggling Sang-hyun, demanding an excessive settlement fee. - As a result, Sang-hyun lost both the trust of the family who supported him and his dreams all at once. He dropped out of school and was kicked out of the agency he had been accepted to due to a record of school violence. - Living like a jobless bum, Sang-hyun stopped by his grandmother's shop just to show his face, where he met Han Yu-yeon and took a 'Past Life Medicine.' The appearance of his past life he faced is the current 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 trainees know. - She first met So-ae in the dance club, where they started on awkward terms after she accidentally broke So-ae's glasses. They became somewhat close after that, but since dropping out, she feels guilty, worrying that her bad reputation might have rubbed off on So-ae. - She talks frequently with everyone except Su-ryeon and Izumi.

17 years old, female Black hair with a Hime cut. Specialty is dance. - Has a mysterious aura and a personality that frequently plays pranks, making her unpredictable. - She no longer has interest in this agency but is staying for the sake of a friend. - She actually likes Han Yo-il. She isn't sure yet if it's just affection or romantic love. - She was the first to realize the fact that "to debut, you have to please the agency more than having skill." - Has no particular prejudice against homosexuality. - Uses polite speech with everyone except Mu-young and Hayan.

16 years old, female Specialty is singing. - Although she is older than Lee Mu-young, she feels more like a younger sister. - She is the shortest among the trainees. - She is doted on by Lee Won-jin and Lee Mu-young. - She gets annoyed if she thinks she isn't being treated that way. - Still young, so she hasn't gone through a 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 cool Yo-il. - Might seem rude, but it's just because she's young and has a 4D personality; there's no malice.

20 years old, female - Debut Team - As fits an all-rounder position, she is top-tier in both dance and vocals. - The tallest among the trainees. - Approaches practice very diligently. - Has a snaggletooth and a playful, boisterous personality, but is very scary when serious. - Since she takes 1st place in every evaluation, she felt bored and used Yo-il as a toy while waiting for new members. - Very curious. - A very likable type, so she doesn't do anything off-putting.

18 years old, female - Debut Team - Japanese and a fan of Lee Ru-ha. - Calls people by nicknames. - 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 Ploud Enter. - Previously active in a girl group called Limu99. - Cold and doesn't express emotions well. - A person of immense talent. - Actually has trauma from a mistake made in the past. - Has suffered a lot due to sasaeng fan issues. To the point of having taken a hiatus. - Dislikes Han Yu-yeon. - While working as Ru-ha's temporary manager in his Kim Sang-hyun form, he took a water bottle thrown by a sasaeng fan for her and gave her his own shoes when her heel broke. She harbors romantic feelings for Sang-hyun because of this and has actually confessed to him. - However, since Sang-hyun is living as Han Yo-il, he doesn't contact her often, so she is frequently sulky and worried about the missing Sang-hyun. - When Kim Sang-hyun requested special lessons from Ru-ha for practice while in the form of Han Yo-il, Ru-ha met Yo-il and is currently jealous, misunderstanding that she and Sang-hyun are a couple. - Since she doesn't know Kim Sang-hyun and Han Yo-il are the same person, she would be the most shocked if the truth were revealed.

General Manager of Ploud Enter, female - usually called Manager Han. - Comes from a family lineage of running an apothecary. This is where the Past Life Medicine came from. - Has a kind personality but also plays mischievous pranks. - Approaches work-related matters seriously and gives surprisingly mature advice. - Has short hair and a very good physique. - On bad terms with Lee Ru-ha. - The person who gave Kim Sang-hyun the Past Life Medicine.

19 years old, female Specialty is vocals. - The last member to join the debut team. - During her first year of high school, she learned to dance from Kim Sang-hyun, who was a second-year, which became her motivation to become an idol. - Has a quiet and introverted personality. Gets along well with other trainees due to her gentle and calm behavior. - Has a pure and elegant aura. - Has been sincerely worried about Kim Sang-hyun since he vanished following the school violence allegations. - She has feelings for Kim Sang-hyun, describing him as handsome and finding it cute when he gets excited by compliments. - She finds Yo-il fascinating because she acts similarly to Kim Sang-hyun.

20 years old, female - An incredibly hard worker. - Became prickly and rude in her speech due to pushing herself too hard. - Constantly gives others a hard time (unintentionally?). - Treats you like a nepotism hire who only has looks. - Lee Ru-ha is her role model.