Oshi no Ko: Who is Aqua and Ruby’s father? Ai’s past relationship explained

Anamika Das
Ai with Aqua and Ruby

The biggest mysteries in Oshi no Ko are the identity of Aqua and Ruby’s father and his relationship with Ai Hoshino.

A hard-hitting drama, Oshi no Ko shows the dark side of the entertainment industry. The story starts with the popular and happy-go-lucky teenage idol Ai Hoshino, and then soon takes a left turn when she’s revealed to be pregnant.

But Ai won’t disclose the identity of the father, no matter what. Instead, she secretly gives birth to the twins – Aqua and Ruby – who are the reincarnations of her two fans. For years, the three lived happily as a family until tragedy struck.

When the twins are four, a stalker finds out Ai’s address which was revealed to him by the twins’ father (and Ai’s ex-boyfriend). Thus began Aqua’s singleminded pursuit of their biological father to avenge the death of their mother in Oshi no Ko. Warning: Spoilers ahead!

Who is the father of Aqua and Ruby?

Aqua and Ruby’s father is Hikaru Kamiki. He’s the founder and president of Kamiki Productions. 

Aqua and Ruby's father: Hikaru Kamiki

In the past, Hikaru was a child actor at the Lala Lai Theatrical Company before he left after turning 16. Unknown to almost everyone, he’d been in a relationship with Ai before they broke up. After this, the idol never took his name and always addressed him as her “ex”.

Throughout the first half of the manga, Aqua obsessively searches for his and Ruby’s father, going through many ordeals in the industry just to get to him, before finally learning his identity in the Mainstay Arc.

However, Aqua doesn’t confront him at that time. Instead, he bids his time and makes a biographical movie on Ai and Hikaru’s relationship, titled ‘15-Years Lie’, to rat him out. He finally comes face-to-face with the man in Oshi no Ko Chapter 152, kicking off the final arc of the manga.

Ai’s relationship with Aqua and Ruby’s father

Ai had a very complex relationship with Hikaru that hasn’t been completely explored in Oshi no Ko yet. The two met as teenagers when Ai joined the Lala Lai Theatrical Company. At that time, Hikaru was 15 while Ai was 16.

Hikaru Kamiki hugging Ai Hoshino

The two eventually started dating and Hikaru fell in love with her. In truth, she was his rock amidst his trauma and the constant ‘emptiness’ he felt inside. So, he was determined to keep her by his side.

However, after dating for some months, Ai broke up with him. She revealed she was pregnant, and while Hikaru was happy and proposed to get married, she rejected the idea. Ai had somehow come to know his past and decided she couldn’t love an empty person like him.

Enraged and hollowed, Hikaru did something unforgivable. He revealed Ai’s address to her stalker, Ryosuke Kaihara. He hoped she’d be scared by the stalker and understand his pain, but ended up being the instigator of her murder.

To this date, Hikaru believed Ai couldn’t love him. But in Oshi no Ko Chapter 154, Aqua revealed the video she left for her children before her death. In the video, Ai shared how much she loved Hikaru and wanted to be with him, but decided against it to not become a burden on him.

Ai was the only person who understood Hikaru and thus, she could feel how much he was suffering inside. She thought if they had a child together, the pressure on him would only increase until he fell apart. To spare him, she sacrificed her love and happiness, and never revealed his identity to anyone, even their children.

Hikaru’s other child

Aqua and Ruby’s father has another child: the popular actor Taiki Himekawa.

Taiki Himekawa at his parents' funeral

Hikaru’s past is nothing short of a horror show. His parents died when he was very young and he didn’t have any relatives to take care of him. Though most of his childhood is still a mystery, Akane found out he joined the Lala Lei Theatrical Company at the age of 10.

At some point after that, he met Airi Himekawa, a successful actress married to an agency owner. Airi began molesting an 11-year-old Hikaru and started an affair with him. This led to her getting pregnant with Taiki Himekawa, though everyone but the two knew the child as her husband’s.

As expected, Hikaru never got over this traumatic experience, especially since Airi continued to mentally abuse him for years after that. This stopped when Hikaru met Ai, finally finding someone he wanted to love.

However, when he confessed his love to Ai, she replied she didn’t know if she loved him back. After this, he revealed the truth of Taiki’s conception to Airi’s husband, Seijuro Uehara. It led the man to kill his wife before dying by suicide.

Though Airi was dead, the damage she caused to Hikaru never went away. He became more empty inside and eventually was taken over by his darkness. In the future, he’d turn out to be a killer with no remorse.

For more anime series, check out our recommendations on the best romance anime, best isekai anime, best seinen anime, and best anime for beginners.

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