The Japanese manga series Oshi no Ko features an extensive cast of characters created by Aka Akasaka and Mengo Yokoyari. The story follows a doctor and his recently deceased patient, reborn as twins to a famous Japanese musical idol, navigating the highs and lows of the Japanese entertainment industry as they grow up together through their lives.
Main characters Ai Hoshino
is a selfless, empathetic but altruisticly deceptive pop idol who rose from humble beginnings. Raised in an orphanage after her parents' absence, she is scouted at age 12 by Strawberry Productions president Ichigo Saitō. Initially doubting she could be an idol due to her inability to understand love, she learns to perform affection for fans, eventually becoming the centerpiece of B-Komachi. At 16, she secretly carries twins, Aquamarine and Ruby, pausing her career to start a family. Returning to idol work after their birth, she is murdered at 20 by an obsessed fan. In her final moments, she realizes her genuine love for her children. Her death drives Aqua to pursue acting as part of his quest for vengeance. Her name, meaning "starry eye", references the distinctive six-pointed stars in her and her children's eyes.
Aquamarine Hoshino / Aqua
, known as , was originally , an obstetrician-gynecologist and devoted fan of Ai Hoshino. Before delivering Ai's twins, Gorou is murdered by her stalker and another doctor had to take over the delivery. However, Gorou reincarnated as her son, Aqua. Following Ai's death, Aqua vows to uncover the truth, theorizing his biological father—someone in the entertainment industry—betrayed her location. He pursues acting to infiltrate the industry and exact revenge. Though he briefly dates Akane, he ends their relationship upon realizing the danger his mission poses for her. Despite growing self-awareness about his destructive obsession, Aqua ultimately stages a murder-suicide with his father, ensuring Ruby's safety before his death. In his final moments, he finds peace, envisioning a hopeful future for Ruby as his consciousness fades.
Ruby Hoshino
, originally , was a terminally ill patient who idolized Gorou before reincarnating as Ai Hoshino's daughter. Carrying Sarina's dream of becoming an idol, Ruby trains diligently after Ai's murder. Though initially rejected due to Aqua's interference, she forms the new B-Komachi with Kana and Mem-cho. Ruby retains Sarina's unrequited love for Gorou, complicating her relationship with Aqua upon discovering his true identity. After overcoming the trauma of Aqua's death, she emerges as an inspirational idol. The ending of the story suggests that despite her initial resistance, Ruby eventually accepted her mother's philosophy, inspiring people with a fake happy and serene persona while hiding sadness and heavy feelings in her heart.
Kana Arima
, once hailed as a child acting prodigy for her ability to cry on command, first meets Aqua when he fills in as a movie extra. As a teenager, her career declines as her talent overshadows peers, forcing her to restrain her performances. Reuniting with Aqua and Ruby in high school, she develops unrequited feelings for Aqua and later joins Ruby's idol group, B-Komachi, becoming its standout member. After two years, she departs to revive her acting career. Her rivalry with Akane stems from their contentious past, where Akane once idolized her. Though Aqua internally acknowledges Kana as the girl closest to him besides Ruby, he never confesses his feelings before his death, leaving Kana tormented by her own unspoken love.
Kana is one of the two protagonists of the light novel spin-off dedicated to her and Akane, which ends with her becoming a famous Japanese and Hollywood actress who tries to fill the void in her heart after Aqua's death with her constant development of her acting career.
Akane Kurokawa
is a stage actress who joins the reality show My Love with a Star Begins Now (LoveNow) to promote her theater troupe. Initially overlooked, she faces severe online harassment after accidentally scratching a co-star, driving her to a suicide attempt that Aqua prevents. By the show's end, her reputation improves, and she shares a staged relationship with Aqua, though she later develops genuine feelings for him. Her admiration for Kana turns to rivalry after a bitter confrontation. A meticulous performer, Akane employs a method-acting approach, deeply analyzing her roles. Discovering Aqua's quest for vengeance, she supports him until he ends their relationship for her safety. Later, she intervenes in his revenge plot, disguising herself as Ruby to thwart an assassination attempt while ensuring Ruby's escape.
Akane is one of the two protagonists of the light novel spin-off dedicated to her and Kana, which ends with her meeting Crow Girl and, fully immersed in the study of the occult, trying to find a way to bring Aqua back to life despite warnings about the dangers of this from her.
Mem-cho
is a YouTuber and TikToker who signs up for LoveNow who is revealed to be aged 25 despite her appearance resembling a high school student. She pursued her dream of becoming an idol, but was unsuccessful due to her family situation during her high school days. She decided to become a streamer and lied about her age to gain many followers. After LoveNow, Aqua recruits her to B-Komachi. She was reluctant due to her age, but ultimately decides to join.
Ichigo Productions Ichigo Saitō
is the president of Strawberry Productions. He is the husband of Miyako Saitō. Ichigo was responsible for the recruitment of Ai Hoshino to B-Komachi. He acts as the caretaker for Aqua and Ruby after Ai's death. Soon after Ai's death, he disappeared for a decade until Ruby tracked him down in order to get advice on her own plans for revenge on her mother's killer. Soon after, he was tracked down by Aqua as well, and expressing a fellow desire for revenge on the killer, assists Aqua with his plans.
Miyako Saitō
is the wife of Ichigo Saitō and acts as the primary caretaker for Aqua and Ruby after Ai's death. She manages Strawberry Productions and keeps the business afloat after the disbandment of the original B-Komachi and the disappearance of Ichigo.
Pieyon
is an anonymous famous physical training YouTuber affiliated with Strawberry Productions, who coaches choreography for B-Komachi members. He makes over 100 million yen a year.
Entertainment industry Stars/performers Melt Narushima
is an actor and model affiliated with Sonic Stage Productions. He was an arrogant and untrained actor when playing the male lead in the Sweet Today live-action adaptation, but still managed to deliver a solid performance for the final scene after being provoked by Aquamarine Hoshino. The experience humbled him and he has worked on improving his acting skills by the time he joined the stage production of Tokyo Blade. He later is expected to play Gorou Amamiya on Director Gotanda's and Aqua's planned Ai biographical movie.
Frill Shiranui
is a student of Youtou High School's Performing Arts Program and one of Ruby's classmates. She is an aloof, attentive and deadpan multi-talented performer who can sing, dance, and act. She later is expected to play Airi Himekawa in Director Gotanda's and Aqua's planned Ai biographical movie after originally being chosen for the role of Ai before allowing Ruby to play the role following a self audition where she was impressed by Ruby's acting skill and conviction.
Minami Kotobuki
is a student in the Performing Arts Program of Youtou High School and a classmate of Ruby and Frill. In the show business industry, she is a friendly but pragmatic and resilient individual who works as a gravure model.
Yuki Sumi
is a fashion model and a participant in the reality dating show The Beginning of My Love With An Idol or LoveNow. Initially a strategic but mature and loyal individual who imagined she would fade into the background, she used her character to create drama and interest.
Nobuyuki Kumano
is a high school second-year dancer and media personality who gained recognition on the reality dating show LoveforReal (also known as The Beginning of My Love With An Idol). Depicted as an honest, empathetic and hardworking individual, he forms a relationship with fellow participant Yuki Sumi at the conclusion of the season.
Kengo Morimoto
is a high school third-year bandsman and musician. He is a quiet, cooperative and supportive individual who participated in the reality dating show We're About to Fall in Love for Real (also known as LoveforReal or LoveNow). Acting as a mature, steady presence, he initially used his participation on the show as a strategic opportunity to gain mainstream exposure for his music career.
Taiki Himekawa
is an award-winning stage actor affiliated with the Lalalai Theatrical Company, first seen as the main star of the Tokyo Blade stage production. It is later revealed that he is also Aqua and Ruby's older half-brother, conceived when his mother, an actress, Airi Himekawa cheated on his legal father with their biological father, Hikaru Kamiki; the latter was eleven years old at that time and an aspiring child actor joining the Lala Lai Theatrical Company when he was molested by Airi resulting in Taiki's birth. However, he himself remains unaware that he is the product of an affair.
Sakuya Kamoshida
is a 22-year-old professional stage actor who is well known within the industry for his extensive experience in 2.5D theatre productions. Though highly talented and dedicated on stage, Sakuya possesses an arrogant, flirtatious personality and a reputation as a womanizer. He initially openly looks down on Melt Narushima's amateur acting abilities. However, after Melt delivers a powerful, breakout performance during the live show, Sakuya gains a newfound professional respect for him and officially acknowledges him as a peer.
Production Taishi Gotanda
is the film director who scouted Aqua and convinced him to become an actor when he saw his potential. After Ai's death, he recruited Aqua as his student at Aqua's request. He is one of the few people who knows the real identity of Aqua. He was once recruited by Ai to make a documentary film of her prior to her death. The creation of this biographical film of Ai's life is part of Aqua's plan of revenge against his father and Ai's killer.
Masaya Kaburagi
is a producer affiliated with an internet TV Station Dot TV!, and producer of the Sweet Today live-action adaptation and the webshow Dig Deep! One Chance. He seems to have deep ties with Ai at the past.
Toshirou Kindaichi
is a sharp and capable director who helped found the Lala Lai Theatrical Company. Kindaichi is known for his ability to bring out the absolute best in his actors, often using clever strategies—such as bringing in outside talent—to push his crew to compete and grow. Following a family tragedy, he also stepped up to raise the talented young actor Taiki Himekawa as his adoptive son.
Yoriko Kichijouji
is the manga artist behind the popular manga series I'll Go With Sweet Today and Abiko's mentor. She also serves as producer for its live action drama where Kana is starring.
Abiko Samejima
is the manga artist behind the manga series Tokyo Blade, and became a producer for its stage play after expressing displeasure with how its adaptation and script was progressing. She used to be Yoriko's assistant and student.
GOA
The sole screenwriter responsible for adapting the manga series Tokyo Blade into a 2.5D Stage Play, before he worked with the author of Tokyo Blade, Abiko Samejima, and created a new screenplay for the adaptation.
Sumiaki Raida
A representative of Magic Floor, an event management company. He is also the lead producer for the 2.5D Stage Play adaptation of Tokyo Blade.
Others Hikaru Kamiki