Who killed Kokushibo in Demon Slayer? An in-depth explanation

Kokushibo as shown in anime (Image via Unfotable)
Kokushibo as shown in anime (Image via Unfotable)

Demon Slayer: Kimetsu no Yaiba has taken the world by storm with its captivating narrative, intricate character development, and visually stunning action sequences. Among the myriad of characters introduced, one that stands out in terms of power and mystery is Kokushibo, the Upper-Rank One demon. His role in the series is pivotal, and the circumstances surrounding his demise have become a topic of significant interest among fans.

The world of Demon Slayer is one filled with demons that terrify and prey on humans. However, not all demons are created equal. The Twelve Kizuki, led by Muzan Kibutsuji, are the most formidable among them. Within this elite group, Kokushibo holds the title of Upper-Rank One, making him one of the most powerful threats the Demon Slayer Corps has ever faced.

But who was Kokushibo before his demonic transformation? And what events led to his eventual downfall? In this article, we will explore the depths of Kokushibo's character, his background, and the epic battle that led to his end.

Disclaimer: This article contains spoilers from Demon Slayer manga series.

Kokushibo's background in Demon Slayer

Before his transformation into the feared demon known as Kokushibo, he was Michikatsu Tsugikuni. He was the older twin brother of Yoriichi Tsugikuni, a legendary figure in the universe of the series known for his unparalleled skills and the creation of the Sun Breathing technique. Michikatsu's transformation into a demon was deeply rooted in his feelings of inadequacy and jealousy towards his younger brother, Yoriichi.

Despite being a skilled swordsman himself, Michikatsu always felt overshadowed by Yoriichi's natural talent and abilities. This envy intensified when he witnessed Yoriichi age gracefully, even after awakening his demon slayer mark, which was believed to limit one's lifespan to 25 years. This mark was a symbol of immense power, but it came at the cost of a shortened life. However, Yoriichi defied this fate, further deepening Michikatsu's feelings of inferiority.

One of Michikatsu's primary fears was the idea of dying young, especially at the age of 25, due to the curse of the demon slayer mark. This fear, combined with his envy of Yoriichi's prolonged life and superior abilities, drove Michikatsu to seek a way to escape this seemingly inevitable fate. This led him to Muzan Kibutsuji, the first and most powerful demon.

By becoming a demon, Michikatsu hoped not only to perfect his techniques as a swordsman but also to escape the curse of the demon slayer mark and the premature death it promised. As a demon, he adopted the name Kokushibo and rose to become the Upper-Rank One of the Twelve Kizuki, second only to Muzan in terms of power.

The final battle against four Demon Slayers

As the Demon Slayer Corps launched their final assault on Muzan and the Kizuki, Kokushibo found himself confronted by four formidable Demon Slayers: Muichiro Tokito, Genya Shinazugawa, Sanemi Shinazugawa, and Gyomei Himejima.

The conflict began when Kokushibo and Muichiro Tokito were taken to the same room inside the Infinity Castle. Kokushibo, showcasing his superior skills, managed to amputate Muichiro’s arm. Impressed by Muichiro's resilience in halting the bleeding, Kokushibo further escalated the situation by impaling Muichiro with his own sword.

As the situation seemed dire for Muichiro, Kokushibo presented him with the option to become a demon loyal to Muzan. However, before any decision could be made, Genya intervened by firing his firearm. Kokushibo, with his swift reflexes, dodged the gunshot and severely injured Genya by severing his arms and torso. Just as Kokushibo was about to deliver the final blow to Genya, Sanemi, the latter's brother, intervened.

The battle between Sanemi and Kokushibo was intense. Kokushibo, with his vast experience, seemed to have the upper hand. However, the tide of the battle shifted with the arrival of Gyomei Himejima, the Rock Hashira. Gyomei, known for his immense physical strength, posed a significant challenge to Kokushibo. The two engaged in a fierce back-and-forth, with Gyomei eventually revealing his Demon Slayer Mark, a secret weapon he had reserved for Muzan.

As the battle raged on, Sanemi and Gyomei showcased their exceptional teamwork, managing to land significant blows on Kokushibo. However, the Upper-Rank One demon was not to be underestimated. Using his unique blade, which had the ability to extend and change shape, Kokushibo managed to injure both Sanemi and Gyomei.

In a twist of events, Muichiro, despite his injuries, rejoined the battle, providing much-needed support to the other Hashira. The combined efforts of the Demon Slayers began to overwhelm Kokushibo. Gyomei, using his flail, managed to shatter Kokushibo's head, while Genya, using his unique bloodthirsty power, restrained the demon. Muichiro, with his blade turned crimson, aimed for Kokushibo's vital organs.

However, Kokushibo, in a desperate attempt, unleashed a barrage of blades from his body, causing severe injuries to Muichiro and Genya and also hurting Sanemi and Gyomei. Despite this, the Demon Slayers pressed on. Genya, using another Blood Power, managed to root another tree into Kokushibo’s back, further restraining him. Gyomei and Sanemi continued their assault, with Muichiro delivering a crucial blow that immobilized Kokushibo.

In his final moments, Kokushibo recalled his past encounter with his younger brother, Yoriichi. Filled with regret and introspection, Kokushibo questioned his life choices and the path he had chosen. As he crumbled to the ground, he realized that he didn't want to become a monster; he simply wanted to be like Yoriichi. In a poignant conclusion to the battle, Kokushibo's last thoughts were of his brother, and he left behind only his shattered flute.


In conclusion, Kokushibo's character in Demon Slayer serves as a testament to the complexities of human emotions and the lengths one might go due to envy and ambition. His journey from a human with aspirations to one of the most potent demons underscores the series' theme of the thin line between good and evil. In the end, his downfall at the hands of the Demon Slayers serves as a reminder of the collective strength of unity and determination.