OSHI NO KO: Aqua and Ruby’s Past Lives Revealed in Volume 13


In “OSHI NO KO,” both Aqua and Ruby are reincarnated individuals who retain memories of their past lives. Although they met in their previous lives, they grew up unaware of each other’s true identities. However, as the story progresses, the moment when their past lives are revealed finally arrives. In this article, we will summarize in which volume and chapter Aqua and Ruby’s past lives are exposed. Additionally, we will explain the circumstances and reasons behind the revelation of Aqua and Ruby’s past lives.

What is OSHI NO KO?

Overview of OSHI NO KO

“OSHI NO KO” is a manga serialized in Weekly Young Jump and Shonen Jump+. While it features a fantasy setting where the protagonists are reincarnated, it also contains many suspense elements. As of February 2024, “OSHI NO KO” has released 13 volumes and has surpassed 15 million copies in circulation. The first season of the TV anime aired in 2023, and following its conclusion, the production of a second season was announced.

Synopsis of OSHI NO KO

Goro, an obstetrician, becomes the doctor in charge of an idol named Ai. On the day of Ai’s delivery, Goro is murdered by an unknown assailant and is reincarnated as Ai’s child, Aqua. Aqua enjoys his new life, but everything changes when Ai is killed by a stalker. Realizing there is a mastermind behind the stalker, Aqua decides to live for the purpose of seeking revenge on the person pulling the strings.

In Which Volume and Chapter Are Aqua and Ruby’s Past Lives Revealed? Why Did Their True Identities Come to Light?

The main story of “OSHI NO KO” begins after Goro is reincarnated as Ai’s child, Aqua. However, Aqua was not the only one reincarnated as Ai’s child. Ruby, Aqua’s twin sister, also retained memories of her past life. Ruby’s past life was a girl named Sarina, who was acquainted with Goro, Aqua’s past life.

Since Aqua and Ruby did not discuss their past lives, they grew up as siblings without knowing each other’s true identities. However, after “OSHI NO KO” enters its “Movie Arc” in chapter 9, Aqua and Ruby’s true identities are finally revealed. In which volume and chapter are Aqua and Ruby’s past lives exposed? Here, we will explain in which chapter their past lives are revealed and the context surrounding it.

In Which Volume and Chapter Are Aqua and Ruby’s Past Lives Revealed?

First, let’s look at which volume and chapter in “OSHI NO KO” reveal Aqua and Ruby’s past lives. Their true identities are revealed in volume 13, chapter 122. Since their reincarnation, Aqua and Ruby have maintained a good relationship. However, due to certain events, Ruby ends up severing ties with Aqua.

The tension between Aqua and Ruby brings a heavy atmosphere to the story. This tension is lifted in chapter 122 when their past lives are revealed. When they learn each other’s true identities and reconcile, the story’s atmosphere brightens significantly.

How and Why Did Aqua and Ruby Discover Each Other’s True Identities and Past Lives?

Now that we know which chapter reveals Aqua and Ruby’s past lives, let’s explore how and why their true identities came to light. Aqua and Ruby had lived without discussing their past lives until a certain event prompted Aqua to realize Ruby’s true identity. He then revealed his own identity, allowing Goro and Sarina to reunite in the truest sense.

So, how did Aqua figure out Ruby’s true identity? There were several clues that hinted at Ruby being Sarina. We will discuss the points that led Aqua to realize Ruby’s past life, along with spoilers of the scene where their past lives are revealed. Additionally, we will summarize why Aqua decided to reveal his own identity, so be sure to check it out.

Spoiler 1: Ruby’s Mental Breakdown

In “OSHI NO KO,” Ruby falls into darkness after discovering Goro’s corpse. Her descent into darkness gradually deepens, but she manages to hold on mentally. Ruby’s mental breakdown occurs when she visits her former home from her past life. At that time, Ruby had been cast as the lead in the movie “15 Years of Lies.” However, as an acting novice, Ruby struggled to perform as she wished.

As she grappled with her struggles and confronted herself, painful memories from her past life resurfaced. Remembering her mother, Ruby decided to visit the home where she lived as Sarina in her past life. Sarina’s mother, Marina Tendouji, had two more children after Sarina’s death and now lives happily with her husband and two children. Witnessing this scene, Ruby was deeply shocked.

Spoiler 2: The Existence of Ai’s Keychain

Realizing that she was unloved by her mother, Ruby began to reject herself. Returning home, she clutched Ai’s keychain and cried uncontrollably. This keychain was a precious memory from her past life with Goro. Ruby had discovered the keychain on Goro’s body and secretly taken it.

When Aqua came to check on Ruby, he noticed the keychain.

Spoiler 3: Ruby’s Use of the Word “Sensei”

Aqua hurriedly attended to Ruby, who had hyperventilated from crying too much. However, Ruby, who was in a cold war with Aqua, rejected his help. Despite her weakened state, Ruby demanded the movie script and declared that she would rise to the top and avenge “Mama” and “Sensei.” “Mama” referred to Ai, and “Sensei” referred to Goro. Ruby had never used the word “Sensei” in front of Aqua before.

There was an unspoken agreement between them not to reveal their past lives, so they avoided mentioning anything related to it. However, in her emotional state, Ruby accidentally called Goro “Sensei” in front of Aqua. Realizing from the keychain and the word “Sensei,” Aqua confirmed that Ruby was Sarina. To stop Ruby from seeking revenge, Aqua called her “Sarina-chan.”

Understanding that Ruby would not listen to him as Aqua, he decided to speak to her as Goro. Ruby was shocked that Aqua knew her name “Sarina” and details from their past conversations in the hospital before reincarnation. Seeing Aqua smile with Ai’s keychain in hand, Ruby realized that Aqua was the reincarnation of Goro.

Spoiler 4: Did Aqua Already Suspect Their Past Lives?

Aqua had noticed Sarina’s resemblance in Ruby since they were babies. Throughout various scenes, Ruby’s actions reminded him of Sarina, leading Aqua to suspect her true identity. However, without certainty, he refrained from mentioning Sarina to Ruby. Even so, Aqua supported Ruby’s dream of becoming an idol, believing she was Sarina.

Spoiler 5: Did Ruby Know Aqua’s Past Life?

Ruby had trusted Aqua but did not pay much attention to his past life. She never considered the possibility that Aqua could be Goro. Therefore, when she realized Aqua’s true identity, she was overwhelmed with emotion and hugged him. Crying, she repeatedly called him “Sensei.”

The Relationship Between Goro and Sarina, and Aqua and Ruby in OSHI NO KO

So far, we have summarized when and how Aqua and Ruby’s past lives are revealed. Next, we will explain the relationship between Goro and Sarina, and Aqua and Ruby in “OSHI NO KO.”

The Relationship Between Goro and Sarina

Goro and Sarina Were Doctor and Patient

Before their reincarnation, Goro and Sarina had a doctor-patient relationship. Goro was an obstetrician, so he had no direct connection to Sarina, a pediatric patient. How did an obstetrician like Goro become close to Sarina? Goro met Sarina while making rounds to various patient rooms. In his spare time, Goro would visit patients who had no visitors, offering emotional support.

One of the patients Goro regularly checked on was Sarina, who later reincarnated as Ruby. Despite being a child, Sarina’s parents rarely visited her. Goro took special care of Sarina, who had been lonely from a young age. Whenever he had time, he would visit her room and support her emotionally.

How Goro Became a Fan of B-Komachi

When Goro is introduced in the first chapter of “OSHI NO KO,” he is seen promoting B-Komachi to his patients. He particularly supports Ai, the center of the group, with an enthusiasm that often surprises those around him. However, Goro was not originally a fan of B-Komachi. His interest in the group began because Sarina loved B-Komachi.

Sarina especially admired Ai and dreamed of becoming an idol like her. Unfortunately, Sarina passed away at the young age of 12 and never achieved her dream of becoming an idol. After her death, Goro began to see Sarina in Ai and became a fervent supporter of Ai.

Did Sarina Have a Crush on Goro?

For Sarina, who did not receive enough affection from her parents, Goro was a pillar of emotional support. Sarina loved Goro dearly and even asked him to marry her. Goro brushed it off by saying, “I’ll think about it when you turn 16,” but Sarina was serious. After reincarnating as Ruby, Sarina clearly states that Goro was her first love. Though she was still a child when she met Goro, it is evident that Sarina had genuine feelings for him.

The Relationship Between Aqua and Ruby

Aqua and Ruby as Brother and Sister

In “OSHI NO KO,” Aqua and Ruby are reincarnated simultaneously as Ai’s twin children. As twins, Aqua and Ruby quickly realize that the other is also a reincarnated individual. However, they do not reveal their past lives to each other and live as siblings, Aqua and Ruby.

Besides being reincarnated, Aqua and Ruby share the common bond of being fans of Ai. From a young age, they work together to support Ai’s career while hiding their true identities. With the same secret and purpose, Aqua and Ruby develop a bond stronger than that of ordinary siblings.

Is Aqua Overprotective of Ruby?

Aqua is extremely overprotective of Ruby in “OSHI NO KO.” He is aware of his overprotectiveness, and Ruby acknowledges that Aqua is a “siscon.” Aqua’s overprotectiveness likely stems from seeing Sarina’s resemblance in Ruby.

Additionally, the trauma of witnessing Ai’s murder contributes to Aqua’s overprotectiveness. In his efforts to protect Ruby from meeting the same fate as Ai, Aqua becomes overly protective.

Ruby Finds Goro’s Corpse

At one point, the new B-Komachi, which Ruby is a part of, visits Takachiho in Miyazaki Prefecture for an MV shoot. Takachiho is where Ai gave birth and where Goro was murdered. After the shoot, while returning to the inn, Ruby’s room key is stolen by a crow. Chasing the crow, she arrives at a secluded shrine.

Behind the shrine is a cave where Ruby discovers a human skeleton. Among the items on the corpse is a nameplate and Ai’s keychain. The keychain was a gift from Ruby’s past life to Goro. Recognizing the keychain, Ruby realizes the corpse is Goro. This discovery marks the beginning of Ruby’s descent into darkness.

Summary of the Scene Where Aqua and Ruby’s Past Lives Are Revealed in OSHI NO KO

Here is a summary of the scene where Aqua and Ruby’s past lives are revealed in “OSHI NO KO.” After learning each other’s true identities, Aqua and Ruby continue to live together as close siblings. Ruby, who had fallen in love with Goro in her past life as Sarina, now clings to Aqua even more after discovering he is Goro. How Ruby’s romantic feelings will be resolved is one of the highlights to look forward to in the story.

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