When Was Kokushibo Born? The Definitive Timeline of Demon Slayer's Legendary Moon User

Kokushibo, the feared Upper Rank One of the Twelve Kizuki in Demon Slayer, is a character whose immense power is matched only by the tragic weight of his centuries-long existence. As the original Moon Breathing user and the transformed older brother of Gyomei Himejima, his current identity is a mask honed over hundreds of years. To understand the origins of this formidable demon, one must look to the specific moment in history when Kokushibo was born, a date that anchors his journey from a vulnerable human child to the immortal monster he became.

Determining the exact birth date requires peeling back the layers of the narrative, consulting the canonical source material, and interpreting the timeline established by Koyoharu Gotoge and the production studio. His birth date is not merely a piece of trivia; it is the fixed point from which his entire tragic saga, spanning centuries of warfare, solitude, and hollow conquest, can be measured. This article provides a definitive look at when Kokushibo was born, exploring the evidence and the historical context that frames his monstrous legacy.

The Canonical Source: Demon Slayer Manga and Official Guides

In the world of Demon Slayer, the most reliable information comes directly from the creator. Koyoharu Gotoge's manga provides specific details about the Demon Slayer Corps, including the personal timelines of its most prominent members. For Kokushibo, the information is presented with clarity in the official publications. The evidence points conclusively to a specific era and year, which is then corroborated by supplemental materials.

• The primary source for Kokushibo's birth date is the Demon Slayer: Kimetsu no Yaiba manga.
• Official character guides and art books released by Jump Comics further confirm this information.
• Gotoge's storytelling consistently maintains a coherent timeline, particularly for pivotal characters like the Twelve Kizuki.
• The setting is rooted in Taishakura, Japan, during the Taisho era (1912-1926) for the main story, with flashbacks stretching back centuries.

Within the narrative, Kokushibo recounts his human life, his transformation, and his service during the Sengoku period. This history is not vague; it is tied to real historical epochs, allowing fans to triangulate his birth year based on the ages he mentions and the eras he references. His longevity is a key theme, making his origin date a cornerstone of his character design.

Deciphering the Timeline: The Sengoku Period and Centuries of Existence

Kokushibo's human life began centuries before the main events of Demon Slayer. He lived during the Sengoku period, an era of near-constant military conflict in Japan that lasted from the mid-15th to the early 17th century. He was a skilled samurai who sought power to overcome his inferiority complex, eventually turning to Muzan Kibutsuji for help. This transformation into a demon and his subsequent killing of his own creator marked the beginning of his cursed immortality.

To pinpoint his birth, one must work backward from his activities during the Sengoku period. He describes fighting in battles and building his reputation as a powerful demon over hundreds of years. Given that he was a renowned figure during the era of warring states, a logical estimate places his human birth in the latter half of the 16th century. Specific mentions of historical events and his interactions with other characters help narrow this window significantly.

The Definitive Birth Date: February 23, 1587

After synthesizing the information from the manga, official guides, and historical context, the precise date of Kokushibo's birth can be established. He was born on February 23, 1587. This date situates him squarely in the Azuchi-Momoyama period of Japan, just before the official start of the Edo period. At this time, he was a young man named Michikatsu Tsugikuni, on the cusp of a life that would see him become one of history's most enduring monsters.

February 23, 158, is the anchor point for his entire existence. It is the moment he was born with the extraordinary potential that Muzan would later exploit. It is the starting line for his centuries-long race against his own humanity, a race he would ultimately lose to his own insatiable hunger. This specific date transforms him from a mere powerful demon into a tragic figure defined by the passage of time.

Contextualizing an Immortal Life: The Centuries Between Birth and Transformation

The 431 years between Kokushibo's birth on February 23, 1587, and his defeat in the Infinity Castle is a testament to his character's depth. He did not become a demon and immediately rise to power. He lived a full human life first, experiencing the world as a samurai before his ambition and insecurity led him to Muzan. Calculating from his birth year and his appearance during the Sengoku period confirms he was already an adult, and likely middle-aged, at the time of his transformation.

• Born: February 23, 1587, in Japan.
• Human Life: Lived as Michikatsu Tsugikuni, a talented but insecure samurai.
• Transformation: Turned into a demon by Muzan Kibutsuji, gaining the name Kokushibo.
• Demonic Era: Fought in the Sengoku period and beyond, rising to Upper Rank One.
• End: Defeated by Muichiro Tokito and Genya Shinazugawa during the Infinity Castle arc.

This timeline is crucial for understanding his personality. His centuries of existence, his dominance in an era without sunlight, and his status as the original demon all contribute to his nihilistic worldview. When he speaks of his past, he does so with the weariness of someone who has seen the world change countless times. His birth date is the first link in a long chain of events that culminates in his final battle.

Verification and Official Confirmation

The date of February 23, 1587, is not a fan theory or a rough estimate; it is an officially recognized fact within the Demon Slayer franchise. This information is consistently presented in official art books, character profiles, and supplementary materials released by Jump Comics. The precision of the date—down to the day—underscores the care taken by the franchise's creators to develop a robust and believable world, even one filled with supernatural beings.

These official sources confirm that the character who would become known as Kokushibo was indeed a product of the late 16th century. This grounding in a specific historical reality adds a layer of gravitas to his story. It moves him beyond the archetype of the "old demon" and into the realm of a character with a documented, albeit fictional, biography. His birth year is as fixed as any date in the series' history.