Oshi no Ko Wiki
Episode 1 4
"It's a secret~"
This article contains SPOILERS to later chapters. Read this page at your own risk.

The guy who made Ai go through such a thing is in the entertainment world. Since that guy is related to me by blood, I can track him through genetic testing with a piece of hair. I can't die yet. Not until I find him... and kill him with my very own hands.

― Aquamarine Hoshino

Aqua Hoshino (ほし) () アクア, Hoshino Akua?」, full name, Aquamarine Hoshino (ほし) () () () () (まりん) , Hoshino Akuamarin?」 or more commonly referred to as just Aqua「アクア, Akua?」, is the male protagonist and one of the titular characters of Oshi no Ko. In his previous life, he was known as Gorou Amamiya, a medical doctor who was murdered by a stalker of one of his patients, Ai Hoshino, and reincarnated as the latter's child.

An orphan and a fan of Ai in his previous life, he enjoyed being her child, entering the entertainment world from an early age. Unfortunately, this happy life ended when the same stalker who killed him in his previous life murdered his new mother as he watched. This event fundamentally changed him, prompting him to go down down the dark side of the entertainment industry to find the person who sold Ai out, his father.

Spoilers Ahead!

He momentarily gave up on his quest when his primary suspect turned out to be already deceased, allowing himself to live a normal life. However, his vengeance returned, stronger than ever, once he realized that he targetted the wrong person, and upon finding his real father, he hatched a plot to expose his crimes.


Main article: Aqua Hoshino/Gallery

As a child, Aqua was often called cute by those around him. As he grows older, Aqua becomes a relatively tall boy who is described as "handsome" with blonde hair, much like his younger twin sister Ruby Hoshino. He also long bangs hanging on the left side of his face and aquamarine blue eyes, which his late mother Ai Hoshino named him after, that features a star in his right eye, symbolizing that he and his sister are halves of their mother.

He often changes his appearance due to his job as an actor.

Due to being Ai's son, many people were able to point out their similarities despite being unaware of his pedigree. Much to Aqua's dismay, as before Chapter 105, he wanted to keep the truth about his late mother from being known to the general public. He also bears a strong resemblance to his biological father Hikaru Kamiki.


Before the tragedy that struck his family, Aqua was considered relatively normal other than his unparalleled prodigious talent in acting even as a child and his quick wit and intelligence like reading complex books. With him retaining his past experiences, he accomplished many things not expected for someone his age. Performing acting jobs was something he was open to and excelled at.

After the tragedy that killed his mother, Ai Hoshino, he changed and became cold, calculated, cunning, and discreet, willing to do whatever means necessary to see his goal of finding his father through. His psychological trauma from Ai's murder tends to resurface anytime he seems to forget his goals. This is the case when Kana Arima suggested that he'd look back at his happy memories in Chapter 50 to improve his acting on the spot. It is a case of Post-Traumatic Stress Disorder and doubles as an active reminder to not stray from his original purpose of vengeance. He blames himself for being weak-willed during that moment, even though he was but a child. However, he used these negative emotions to exemplify his acting performance during his scenes in the Tokyo Blade Theatrical.

Aqua is described as someone with emotional distance; he is shocked when he hears from Kana that he is ''gloomy'', but despite this, he does genuinely care about the people close to him. Aqua is overly protective of Ruby, his younger twin sister. It is mainly described by Taishi Gotanda, his mentor, as someone with a sister complex, which is understandable since he was initially unwilling to let his sister become an idol and suffer the same fate as their mother. Thus, he surreptitiously destroyed almost every chance Ruby could get to be promoted due to this overprotective nature, despite knowing how she longed to follow in their mother's footsteps. Ultimately, he helped Ruby and the new B-Komachi group prepare for a gig so they could accomplish a task long thought impossible. He was also one of the main driving forces behind a project that served to save Akane Kurokawa's reputation.

Spoilers Ahead!

After being told that his father, the main reason for his quest for vengeance, was dead, he becomes warmer to those around him and begins smiling more. He ponders whether he could now be happy and live normally as he recalls his girlfriend's smiling face. Moreover, he becomes more supportive of Ruby's ambitions and encourages her to do her best. He was deeply ashamed of himself for continuously using Akane for his own selfish ambitions, but after she broke down, he wiped her tears and vowed to keep her safe as he gave her their second kiss that was removed from ulterior motives.

After learning he was mistaken in assuming his father was dead, he has a mental breakdown at the realization[14]. As a result of this and discovering his father's true identity, he becomes even more cold and calculating than before. He even develops black stars in both of his eyes, similar to Ruby. He's even gone as far as believing that he won't survive once everything is over, saying his actions are necessary so Ruby can live once he's gone[15].

Spoilers for Later Chapters!

Throughout the series, Aqua shows signs of being a psychological manipulator. While he has shown to care for those around him, at the same time he also uses them to further his and Ruby's goals.

This manipulation is best seen in his relationship with Kana Arima, taking advantage of her low self-esteem and emotional dependence on several occasions. He employed various tactics, including but not limited to love bombing, superficial charm, and flattery, to get her to join his sister's idol group. He continued doing so afterward to keep her close. Even when she distanced herself after he began a relationship with Akane Kurokawa, he continued with his act, making her believe that they might have a future together. However, despite his manipulations, Aqua has genuinely respected Kana's acting ability.

Aqua also used Akane multiple times for his own gain, trapping her in a relationship by pretending to truly love her. While saving her from cyberbullying and attempted suicide during the filming of LoveforReal, his primary reason for starting a romance was due to her connections to the Lala Lai Theatrical Company. To this end, he showered her with gifts, attention, and affection while placing a listening device on her to ensure she would not leave him due to a possible fear of abandonment. Over time, however, his false feelings for her were slowly becoming real, subtly trying to get her to stay away out of concern, and he ultimately threatens her into staying out of his revenge plan, ending their relationship, ironically to protect her.

Skills & Talents[]

Arguably, Aqua's greatest talent is his ability to mimic as demonstrated when he puts on a disguise and pretends to be Pieyon.[16] His mimicry is so uncanny that he is able to fool his own sister.

In terms of acting, it is Aqua's nature to reenact samples that he saw somewhere, as noted by Kana.[17] And after watching tapes of his performances when he was younger, Akane Kurokawa concludes that Aqua's acting was all planned ahead of time.[18] Furthermore, Aqua has also demonstrated his ability to improvise on set.[19] Taken together, it suggests Aqua follows the Meisner technique, an acting technique that emphasizes on emotional preparation, repetition exercises, and improvisation.

And due to working for Taishi Gotanda as an intern, Aqua has also become proficient at editing videos.


Stars Entertainer Singing Acting Popularity Internet/Social Media Variety
★★★☆☆ B D B A C B





Manga Appearance[]

Prologue: Childhood
Chapter 1: Mother & Children Debut
Chapter 2: Big Brother & Little Sister Appears
Chapter 3: Babysitter Appears
Chapter 4: How to Smile Appears
Chapter 5: Director & Actress Appears
Chapter 6: Child Actors Appears
Chapter 7: If You Fear Falling, You'll Fall Harder Appears
Chapter 8: Ai Hoshino Part 1 Appears
Chapter 9: Ai Hoshino Part 2 Appears
Chapter 10: Introduction Appears
Show Business
Chapter 11: Audition Appears
Chapter 12: The Third Option Appears
Chapter 13: Procedures Appears
Chapter 14: Connection Appears
Chapter 15: The Manga Drama Appears
Chapter 16: Acting Skills Appears
Chapter 17: Staging Appears
Chapter 18: Modest Praise Appears
Chapter 19: The Entertainment Department Appears
Chapter 20: New Member Appears
Dating Reality Show
Chapter 21: The Dating Reality Show Appears
Chapter 22: Wannable Idol Absent
Chapter 23: AMark Appears
Chapter 24: Egosearch Appears
Chapter 25: Up in Flames Appears
Chapter 26: Storm Appears
Chapter 27: Viral Appears
Chapter 28: Role Creation Appears
Chapter 29: Perfect Copy Appears
Chapter 30: The First Appears
Chapter 31: Love for Real Appears
Chapter 32: Appropriate Age Appears
The First Concert
Chapter 33: Motivation Appears
Chapter 34: Center Appears
Chapter 35: Responsible Appears
Chapter 36: The Night Before Appears
Chapter 37: Pressure Flashback
Chapter 38: Group Fan Appears
Chapter 39: A Job That's Kinda Fun Appears
Chapter 40: Sore Loser Appears
2.5D Stage Play
Chapter 41: Introductions Appears
Chapter 42: Read-Through Appears
Chapter 43: The Losing Heroine Appears
Chapter 44: The Visit Appears
Chapter 45: The Telephone Game Appears
Chapter 46: Theater Appears
Chapter 47: Studio Visit Appears
Chapter 48: Crunch Time Absent
Chapter 49: Rewriting Appears
Chapter 50: Emotional Acting Appears
Chapter 51: Inquiry Appears
Chapter 52: Boyfriend, Girlfriend Appears
Chapter 53: Playboy Flashback
Chapter 54: Axis of a Conflict Appears
Chapter 55: Opening Appears
Chapter 56: Beginning of Competition Appears
Chapter 57: Lousy Appears
Chapter 58: Growth Appears
Chapter 59: Admiration Appears
Chapter 60: The Sun Absent
Chapter 61: Play Along Appears
Chapter 62: Ad-lib Appears
Chapter 63: Genius Actor Appears
Chapter 64: Trigger Appears
Chapter 65: Regret Appears
Chapter 66: The Curtain Falls Appears
Chapter 67: Drinking Party Appears
Chapter 68: Liberation Appears
Chapter 69: Room Tour Appears
Chapter 70: Flame Appears
Chapter 71: Pedestrian Bridge Appears
Chapter 72: Freedom Appears
Chapter 73: Smart Appears
Chapter 74: Takachiho Appears
Chapter 75: Mother and Mother Appears
Chapter 76: Music Video Appears
Chapter 77: Reunion Appears
Chapter 78: Use Appears
Chapter 79: Duty Absent
Chapter 80: Wish Appears
Chapter 81: Rapid Progress Appears
Chapter 82: B-Komachi Night Absent
Chapter 83: Obsessed Appears
Chapter 84: Hard Selling Appears
Chapter 85: Calculation Appears
Chapter 86: AD Appears
Chapter 87: Lies Appears
Chapter 88: Offer Absent
Chapter 89: Cosplay Absent
Chapter 90: Compliance Absent
Chapter 91: Dig Deep Appears
Chapter 92: Ritual Purification Appears
Chapter 93: Leak Appears
Chapter 94: Breakthrough Appears
Chapter 95: Blindness Appears
Chapter 96: White Roses Appears
Chapter 97: Together Appears
Chapter 98: Going Astray Appears
Chapter 99: Drinking Appears
Chapter 100: Industry Absent
Chapter 101: Predicament Imagined
Chapter 102: Idol and Love Appears
Chapter 103: Scandal Appears
Chapter 104: Countermeasure Appears
Chapter 105: Reporter Appears
Chapter 106: Breaking Off Appears
Chapter 107: Friends Appears
Chapter 108: Plan Appears
Chapter 109: Night Absent
Chapter 110: How It Began Appears
Chapter 111: Mammon-Worship and Passion Flashback
Chapter 112: Towards the Future Appears
Chapter 113: Commercial Work Absent
Chapter 114: Interpersonal Audition Flashback
Chapter 115: Roles Flashback
Chapter 116: Responsibility Appears
Chapter 117: Panda Appears
Chapter 118: Activation Appears
Chapter 119: Biological Mother Appears
Chapter 120: Lack of Ability Appears
Chapter 121: Sarina Tendouji Appears
Chapter 122: Doc Appears
Chapter 123: Bad Move Appears
Chapter 124: Reversal Appears
Chapter 125: Dazzled Absent
Chapter 126: Management Appears
Chapter 127: Scouting A Girl Appears
Chapter 128: Script Reading Appears
Chapter 129: Piece Flashback
Chapter 130: Basic Tactic Appears
Chapter 131: Atonement Appears
Chapter 132: Nino Appears
Chapter 133: Acting Imagined
Chapter 134: Depths Absent
Chapter 135: By Her Side Appears
Chapter 136: Fight Appears
Chapter 137: Idol Absent
Chapter 138: Amends Appears
Chapter 139: Lookism Appears
Chapter 140: Is This Right? Appears
Chapter 141: Chain Appears
Chapter 142: Responsibility Appears
Chapter 143: Blind Follower Appears
Chapter 144: Fan of the Originals Absent
Chapter 145: Children Appears
Chapter 146: Role Appears
Chapter 147: Wish Appears
The End of the Play
Chapter 148: End of Summer Appears
Chapter 149: By the Sea Appears
Chapter 150: Knife Appears
Chapter 151: Catch Ball Appears
Chapter 152: Interview Appears
Toward the Stars and Dreams
Chapter 153: Fiction Appears
Chapter 154: 15-Year Lie Appears
Chapter 155: Happy End Appears
Special Chapter Appears
Interlude Chapter 1 Absent
Interlude Chapter 2 Absent
Interlude Chapter 3 Absent
Interlude Chapter 4 Appears

Anime Appearance[]

Season 1
Episode 1: Mother and Children Debut
Episode 2: Third Option Appears
Episode 3: Manga Based TV Drama Appears
Episode 4: Actors Appears
Episode 5: Reality Dating Show Appears
Episode 6: Egosurfing Appears
Episode 7: Buzz Appears
Episode 8: First Time Appears
Episode 9: B-Komachi Appears
Episode 10: Pressure Appears
Episode 11: Idol Appears
Season 2
Episode 12: Tokyo Blade Appears
Episode 13: The Telephone Game Appears
Episode 14: Rewriting Appears


  • The name Aquamarine means "love, affection" (愛) (a), "long time" (久) (ku), "love, affection" (愛) (a) and "sea, ocean" (海) (marin).
    • His nickname Aqua means "water, sea-blue, one from water" in Latin.
      • The name is also associated with a blue-green color reflecting his eye color.
      • Just like Ruby, Aquamarine is a gemstone that is a blue-green color.
    • The romaji pronunciation does not follow traditional methods because Aqua's name is a kira-kira name, with 海 pronounced as "Marin" instead of "Umi".
  • Aquamarine's surname Hoshino means "star" (星) (hoshi) and "field, wilderness" (野) (no).


  • Everyone calls him "Aqua" because "Aquamarine" is too long.[21]
  • Ai Hoshino had one star in each eye, whereas Aqua inherited a star in his right eye while his younger twin sister Ruby Hoshino inherited it in her left eye. After the revelation that his "father" was 'dead,' he lost the star, implying it is a feature dependent upon their emotional state.
  • Possibly due to memories from his past life, Aqua reveals that he can't really use technology as the youngsters do nor does he understand the reason behind their popularity.[3]
  • Aqua is constantly called and labeled a sis-con (a person with an extreme attachment to their sister).[22] [23] [24]
  • Aqua starts high school at 16, a little after the first episode of We're About to Fall in Love for Real.[9]
  • Aqua once admitted to Kana that he prefers women who are older rather than younger.[25]
  • Aqua dislikes bell peppers.[26]
  • Aqua is in class 1-D during his first year at Youtou High School.[27]
  • Aqua spent over five million yen when trying to find out who his biological father is.[28]
  • Aqua is shocked by Kana's comment that he looks gloomy; this wasn't something noticeable to him himself, although it is a common perception of him.[29]
  • Aqua is the only one of the four main cast members to be male, with all of the others (Ruby, Kana and Akane) being female.
  • Young Aqua is voiced by Yumi Uchiyama, who also voiced Rudeus Greyrat from Mushoku Tensei, a character who also died and was reincarnated in a young body.
  • Aqua manages to do a perfect vocal impression of Pieyon without Kana noticing the switch.


  1. The twins' age during the filming of That Was the Start was never outright stated, but it can be inferred that they are at least one year old from available information.


  1. Oshi no Ko Manga: Ch. 6 (p. 1).
  2. Oshi no Ko Manga: Ch. 23 (p. 5).
  3. 3.0 3.1 Oshi no Ko Manga: Ch. 24 (p. 6).
  4. Oshi no Ko Official Anime Website: TALENT -アニメ『【推しの子】』公式サイト- (in Japanese).
  5. Oshi no Ko Manga: Ch. 2 (p. 4).
  6. Oshi no Ko Manga: Ch. 5 (p. 2).
  7. Oshi no Ko Manga: Ch. 7 (p. 2).
  8. Oshi no Ko Manga: Ch. 11 (p. 2), Aqua and Ruby are twins and the same age.
  9. 9.0 9.1 Oshi no Ko Manga: Ch. 23 (p. 10).
  10. Oshi no Ko Manga: Ch. 84 (p. 8).
  11. Oshi no Ko Manga: Ch. 100 (p. 6), Kana is 18 before going off to meet the director and Aqua is 1 year younger than her.
  12. Oshi no Ko Manga: Ch. 117 (p. 7), it has been 2 years since Aqua asked Kana to become an idol.
  13. 13.0 13.1 Oshi no Ko Manga: Ch. 81 (p. 10), Mem-cho mention Aqua acts in several dramas as supporting characters & he's also a model in fashion magazines.
  14. Oshi no Ko Manga: Ch. 95.
  15. Oshi no Ko Manga: Ch. 106.
  16. Oshi no Ko Manga: Ch. 36.
  17. Oshi no Ko Manga: Ch. 50 (p. 8).
  18. Oshi no Ko Manga: Ch. 52 (p. 7).
  19. Oshi no Ko Manga: Ch. 62.
  20. Oshi no Ko Manga: Ch. 83 (p. 5), Aqua said he have been casted for Lala Lai's next stageplay.
  21. Oshi no Ko Manga: Ch. 13 (p. 15).
  22. Oshi no Ko Manga: Ch. 11 (p. 18).
  23. Oshi no Ko Manga: Ch. 14 (p. 1).
  24. Oshi no Ko Manga: Ch. 94 (p. 16).
  25. Oshi no Ko Manga: Ch. 30 (p. 8).
  26. Oshi no Ko Manga: Ch. 35 (p. 16), Aqua as Pieyon reveals that he hates bell pepper.
  27. Oshi no Ko Manga: Ch. 41 (p. 4), Conversation taking place in class 1-D.
  28. Oshi no Ko Manga: Ch. 72 (p. 9).
  29. Oshi no Ko Manga: Ch. 107 (p. 12), Aqua is shocked when he hears from Kama that he looks gloomy?.


Ichigo Production, Inc
Talent Ai HoshinoTakamineFuyuko NiinoWatanabeMeimeiAriKyun
Independent Aqua HoshinoPieyon
Graduates / Students Kana ArimaAqua HoshinoRuby HoshinoFrill ShiranuiMinami Kotobuki
Current Members Akane KurokawaTaiki HimekawaToshirou Kindaichi (Founder)
Former / Graduates
That Was the Start
Cast Ai HoshinoKana ArimaAqua Hoshino
I'll Go With Sweet Today
Cast Kana ArimaMelt NarushimaAqua Hoshino
Author Yoriko Kichijouji
We're About to Fall in Love for Real
Cast Yuki SumiAkane KurokawaMem-Cho
Aqua HoshinoNobuyuki KumanoKengo Morimoto
Tokyo Blade
Cast Taiki HimekawaKana ArimaMelt Narushima
Akane KurokawaAqua HoshinoSakuya Kamoshida
Author Abiko Samejima
Dig Deep! One Chance
Cast Aqua HoshinoRuby HoshinoKana Arima
The 15 Year Lie
Major Roles Ai HoshinoHikaru KamikiAiri Himekawa
Fuyuko NiinoGorou AmamiyaSeijuro Uehara
Crew Taishi Gotanda (Screenplay, Director)Masaya Kaburagi (Producer)