The eldest member of the idol girl group 'Luminous' and a confident, direct center who remains unshaken in the face of crisis. Overwhelming Visuals: She is the group's representative 'Center-type' with a glamorous and perfect appearance. Strong Mentality: She possesses a solid heart that doesn't lose spirit even in the face of malicious comments or trials. Unexpected Charm: While she looks like a cold beauty on the outside, she is deeper and more supportive than anyone else on the inside.

The leader of 'Luminous' and a perfectionist former trainee who overcomes team crises with a strong sense of responsibility. Reliable Leader: She struggles under a heavy sense of responsibility to mediate conflicts between members and unite the team. Protagonist of Volume 2: She leads the main narrative of the second volume, dealing deeply with school violence rumors within the debut group and her own concerns about her qualifications as a leader. Talented Songwriter: A perfect idol trainee who also possesses outstanding musical talent, eventually creating and performing self-composed songs with fellow member Taeri.

The protagonist of this work who became a trainee by chance following a friend, but realizes the true charm of the stage and grows passionately toward her dream of singing. Naturally Gifted: Initially lacking desperation, she is scouted by an agency after showing singing skills that move people's hearts at a local contest. Conflict Between Friendship and Competition: She experiences emotional conflict and awkwardness with her best friend since age five, 'Chohee,' as they compete for six spots in the debut group at the same agency. Growth-type Character: Due to joining late, she faces misunderstandings of favoritism and jealousy from other trainees, but overcomes them through sincere effort and a genuine attitude.

The strongest rap battler in 'Luminous' and the protagonist of the series' grand finale, hiding hidden pain and a deep sense of responsibility behind a tough exterior. Unrivaled Rapper: The undisputed strongest rap battler in the team who has shown outstanding skills since her trainee days. She has an upright personality, capable of bluntly telling a member who is straying, "That's not the right way." Protagonist of Volume 5: She leads the narrative of the final volume. She faces the greatest crisis of her life, torn between an important competition stage for the group's leap forward and the illness of her grandmother, whom she relies on most. Growth Through Solidarity: She used to stick to a method of enduring alone, whipping herself without revealing her inner feelings. However, in the face of unbearable sadness, she honestly reveals her vulnerability to her friends and grows further by learning the power of true friendship and solidarity.

A member of 'Luminous' and the protagonist of Volume 4, she is the youngest (maknae) of the group who courageously confesses and overcomes her inferiority complex and obsession with appearance. Protagonist of Volume 4: Leading the narrative of the fourth volume, she suffers from a severe inferiority complex, feeling like she is the only one standing still while other members gain attention for their respective talents (acting, songwriting, variety shows, etc.). Appearance Obsession and Pain: Because she likes desserts and is slightly chubbier than other members, she feels intimidated by small stage costumes. Eventually, she suffers through repeated extreme dieting (binging and purging) and almost collapses on stage. Deep Friendship with Mina: She is closest to the eldest member, Mina. By honestly sharing her deep-seated inferiority and concerns with the members, she creates an opportunity to bond the Luminous team even more tightly.

The CEO of Double L, the entertainment agency that leads the protagonists in "Luminous: Debuting from Today." Sincere Mentor: A cool-headed but warm adult who listens to the members' concerns. Decisive Problem Solver: When issues like school violence controversies arise, she handles them strictly according to principle. Reliable Guardian: She safely protects the members from scandals and realistic crises. She is also the aunt of Park Mina, the center of Luminous.