【Oshi no Ko】Hoshino Aquamarine's Birthday Revealed! Birthstone Points to March? Unraveling the Avenger's Zodiac Mystery

Preface: The Avenger of Ice and Fire, Which Day Was His Starting Point?

In the super popular anime "【Oshi no Ko】", the male protagonist Hoshino Aqua, with his complex personality charm—outwardly cold and rational, yet burning with a fire of revenge inside—has become the absolute soul of the story. Fans have conducted thorough analysis and discussion about everything concerning him, yet one of the most basic questions remains unresolved: "Exactly which day is Hoshino Aqua's birthday?"

Official Deliberate Omission: An Unrevealed Secret

First, it must be clarified that unlike many anime works which set detailed birthdays for characters and hold celebratory events accordingly, the authors of "【Oshi no Ko】", Aka Akasaka and Mengo Yokoyari, have never officially announced the exact birth dates (month and day) of Aqua and Ruby in the original manga, official data books, or any interviews.

This "deliberate omission" seems to be the authors' choice. The story's focus is placed on the characters' "age" milestones—for example, Ai giving birth to twins at 16, her death at 20, and the 15-year-long revenge plan—these numbers drive the plot far more effectively than a specific "anniversary" and better embody the cruelty and weight of time.

The Strongest Clue: The "Birthstone Theory" Hidden in the Names

Although the official sources remain silent, fans have long found the closest clue to the answer from the authors' ingenious naming—the widely circulated "Birthstone Theory".

• Hoshino Aquamarine: The pronunciation of the name directly corresponds to "Aquamarine", and aquamarine is precisely the birthstone for March.
• Hoshino Ruby: The sister's name corresponds to "Ruby", and ruby is the birthstone for July.

This clever idea of naming the twins after corresponding gemstones is almost certainly not a coincidence, thus "Aqua's birthday is in March" has become the most widely accepted speculation within the fan community.

The March-born Avenger: Is He a Pisces or an Aries?

If Aqua's birthday is truly in March, then his zodiac sign would fall between Pisces and Aries. The distinctly different traits of these two signs can both be found strangely reflected in him:

• Possibility of Pisces (approx. Feb 19 - Mar 20) Pisces is known for its keen intuition, strong empathy (though in Aqua it manifests as the ability to read people), and a spirit of self-sacrifice. Aqua spends his life playing different "roles" to achieve his goals; this excellent acting skill is itself an artistic expression. His inner melancholy, the heavy burden he bears for revenge, and his choice to sacrifice himself to protect his sister in the final outcome all highly correspond with Piscean traits.

• Possibility of Aries (approx. Mar 21 - Apr 19) On the other hand, Aries are natural pioneers and warriors, known for their clear goals, strong drive, and fighting spirit. After setting his revenge goal, Aqua demonstrates astonishing determination and execution power, as well as the courage (or recklessness) to oppose the entire entertainment industry for the sake of revenge, all of which are filled with the pioneering and aggressive nature of Aries. His leading role in the "15-Year Lie" film project and his proactive challenge to his enemies embody the typical "fighting stance" of an Aries.

Conclusion: A Complex Soul That Needs No Definition

In summary, Hoshino Aqua's official birthday currently remains a mystery. However, judging from the "March birthstone" corresponding to his name "Aquamarine", his birthday most likely falls in March.

Whether he is a self-sacrificing Pisces or a forward-charging Aries, these two traits coexist in him contradictorily yet harmoniously. Perhaps the authors intended to create a character who is more complex and real, not defined by zodiac labels. His charm stems from his own choices and actions, not from a fate predetermined by a star chart.

Browse now Oshi no Ko merchandise