The ugliness of not admitting defeat even though they took my head, chopped me up and crushed me. Living in disgrace. Have I lived hundreds of years for this? Was I so afraid of defeat that I became a monster? Did I want to be strong even if it meant eating people? Did I become this miserable creature because I didn't want to die? No. Yoriichi... I just wanted to be you.
— Kokushibo's final moments in Samurai
Over four centuries ago during the Sengoku Era, Kokushibo was a human by the name of Michikatsu Tsugikuni (
As a demon, Kokushibo took the form of a pale-skinned, tall and muscular man with long and spiky hair with red tips that he kept in a ponytail. His most notable feature is the three sets of eyes on his face with red sclera and yellow irises. His middle set of eyes featured the kanji of Upper Rank (
Kokushibo wore a purple-and-black-patterned nagagi kimono and black hakama pants tied with a white cloth. He carried a fleshy katana at his waist that had eyes in the space between the tsuka wrapping of the handle of his sword. The guard and blade were also later revealed to have eyes and veins.
As a human, Kokushibo's appearance was nearly identical to his demon form, with the exception of the number of eyes, his prominent eyebrows, and notably less pale skin. His eyes had brown irises and normal, white sclera as a human. As a child, he was usually seen wearing a white kimono as opposed to the purple-and-black patterned one he is seen wearing as an adult.
After being beheaded by Sanemi Shinazugawa and Gyomei Himejima, Kokushibo evolved into a grotesque version of his demon appearance, with protruding fangs, a pair of horns, pointed nails, and several sharp fleshy appendages from the back of his body.
Kokushibo was often very reserved as a demon, and with such little knowledge about the Upper Ranks, not much was originally known about him. He was an adamant rule-follower, punctual, and he showed a great deal of respect to the hierarchy of the Twelve Kizuki - as seen at the Upper Rank gathering Kokushibo was portrayed to be humble as well, and he did not hesitate to admit his failure or complain of any difficulty. He displayed a strong sense of loyalty towards Muzan Kibutsuji, with most of his actions being done with the sole purpose of fulfilling Muzan's goals. Despite exhibiting outward reservation and humility, he was also rather cold; his words could be extremely harsh, especially when reprimanding individuals. His threats came off as nothing short of cruel and overwhelmingly serious, and he demanded absolute obedience. Kokushibo has also been shown to be genuinely delighted when his peers challenge him, particularly in the case of Akaza. However, due to this, he also felt irritation and insulted him after he realized he died.
He had a complex relationship with his human past. He showed something of warmth towards his descendant Muichiro Tokito, commending his skills and resolve, and moved to convert Muichiro into a Demon to spare his life. At the same time, he referred to Muichiro and his abilities as the natural result of his "cells" being passed down.
It was revealed that as a human, Kokushibo harbored an immense sense of envy towards his younger twin brother, Yoriichi Tsugikuni, for his natural talent and incredible abilities. These feelings of jealousy and contempt strengthened upon seeing his brother aged to an old man despite Yoriichi awakening his Demon Slayer Mark, which was to supposedly doom him to die at the age of 25. However, despite this immense jealousy, spite, and outright hatred he harbored for Yoriichi, he still deeply cared for and loved his brother, as seen when he was touched by Yoriichi treasuring the handmade flute he had made for him as children. Kokushibo shed genuine tears over his brother's death, and even went as far as keeping the flute itself for the following centuries as a memento to his beloved and hated younger brother.
In his duel against Gyomei Himejima, the demon's banter suggested a fear of death. When Gyomei's marks appeared, Kokushibo preemptively bemoaned the loss of a talented fighter and urged him to become a Demon to continue honing his skills. He seemed surprised when Gyomei vehemently rejected his offer and called his mentality pathetic.
Likely a result of his inferiority complex and his immense desire for strength, Kokushibo feared the prospect of suffering defeat. So much so, he became increasingly more aggressive and agitated when being pushed further into a corner, causing him to become more desperate in his attacks and the use of his demon power. During his battle with the Hashira, he came to realize the steep price he had paid for the strength he so much desired, becoming an ugly monster far away from his idealized dream of a strong samurai just like his brother, symbolizing how much his deep ambitions and resentment had warped him for the worst. Later upon his death, he greatly lamented and regretted his choices in his life and began to openly question himself if the path he walked was truly the right one.
Overall Abilities: Kokushibo was an extraordinarily powerful demon, proven to be the strongest of the Twelve Kizuki and the second strongest demon in the series, just behind Muzan Kibutsuji. As one of the oldest demons in the series, he had battled numerous Demon Slayers and obtained vast experience and knowledge of combat. He was able to easily decipher the techniques and skills of at least two Hashira and overwhelm them in battle. As a Breath Style user, he possessed tremendous levels of strength and reflexes that were further enhanced by his demon physiology.
These overall abilities and skills allowed Kokushibo to defeat two Hashira with minimal effort and then fight against both Sanemi and Gyomei, the latter of which was considered to be the most powerful Demon Slayer in the Demon Slayer Corps. Even when Gyomei and Sanemi awakened their Demon Slayer Marks, which increased one's physical abilities way above their normal limit, he was still capable of holding his own against the both of them simultaneously.
When he started using his more of his power, Kokushibo managed to overwhelm both Gyomei and Sanemi, both of whom were boosted by their Demon Slayer Marks. As a testament to his might, it ultimately took a combo of attacks from Gyomei, Sanemi, Muichiro and Genya to even land a significant injury on him. In the end, Kokushibo's loss was mostly a result of his sudden choice to stop regenerating and began crumbling due to realizing his mistake, rather than the skills of his opponents.
Demon Slayer Mark: A special Mark worn by certain "awakened" Demon Slayers that resembles Demon Marks. Its specific abilities are unknown, but what is know is that it drastically improves the abilities of the Demon Slayer, making them much stronger, faster and able to react quicker than what they can achieve normally, though at the cost of being cursed to die at the age of 25. As a Demon, not only was Kokushibo no longer bound by the curse, but the Mark's abilities were enhanced even further than when he was a human.
- Transparent World: Similar to Tanjiro, Kokushibo has obtained the ability to see the "Transparent World" through the use of his three pairs of eyes. This allows him to see the muscles, blood flow, and joint movement of his opponents. He can accurately predict and anticipate the movements and attacks of his opponents with this ability. He was also able to identify that Muichiro was his descendant, immediately discern the skill level of Muichiro, Sanemi, and Gyomei with one look, and see that Genya Shinazugawa consumed Demons to gain strength by looking into his cellular structures.
Enhanced Vision: As Kokushibo possesses 3 pairs of eyes, his eyesight has not only been augmented physically, but supernaturally as well, granting him superhuman kinetic vision similar to Kanao Tsuyuri that make the world seem to move in slow-motion in addition to predicting opponents' attacks and movements by observing the subtle shifts of their muscles, joints and the slight movements of their eyes, which is further enhanced by his access to the Transparent World through this same superhuman vision. This grants him immense reaction and reflex speeds and allow him to perceive multiple attacks from different directions seemingly outside his line of sight, and to see from long distances.
Extrasensory Perception: Kokushibo can detect presences of others outside of his range of perception, as shown when he dodged Genya Shinazugawa's gunshots and appeared directly behind him despite Kokushibo not looking at Genya at all. With the Transparent World, he could perceive the bodily structures and see through the bodies' of his opponents and use this information to predict their attacks and movements. He also seems be extremely proficient in the use of the Transparent World, being able to trace back the heritage of a young child back to his own bloodline with a simple glance. He's also able to immediately determine how strong his opponents are by looking at their muscles and bodily structure. Outside of his vision, Kokushibo also seems to be able to keep track of the locations of his peers around the Infinity Castle, evident as he no longer felt Akaza's presence when he died.
Flesh Manipulation: Like all Demons, Kokushibo possesses the ability to manipulate his own flesh, although at a much higher caliber since he assimilated a lot of Muzan's blood. He used this ability to grant himself multiple eyes that augment his vision to supernatural levels. He has also used this ability to create an extremely durable and sharp katana, complete with a handguard and scabbard. Because of this, his katana can never be destroyed as he can regenerate it like he would with normal wounds.
- Sword Manipulation: As an extension of his flesh manipulation ability, Kokushibo can manipulate a detached part of his body in the form of his katana. This allows him to easily regenerate parts of if it was destroyed or damaged as he would his body, which was shown numerous times when the blade returns to its original shape when Gyomei Himejima or Sanemi Shinazugawa damaged it with their attacks. Furthermore, he can freely manipulate the form of the blade, shown when he grew three additional blades from the original blade to increase its reach and further increase its size. While engaging in combat, he can manipulate the length and size of his sword strikes, allowing him to cover a distance normally unachievable by a human swordsman. Later, Kokushibo also displayed the ability to grow and protrude multiple blades from his own body, allowing him to perform a multitude of slashes from them without a swinging motion. This attack was powerful enough to easily blow away two Hashira and destroy Genya's Blood Demon Art, as well as slice in half numerous columns in the room, from just its activation.
- Monstrous Transformation: Later, upon re-growing his head while battling Gyomei and Sanemi, Kokushibo was able to transform himself into a more monstrous form with several appendages on his back that enhanced all of his abilities and powers to nearly the same level as the Demon King, Muzan Kibutsuji.
Immense Durability: Kokushibo had displayed immense physical durability as seen when despite Gyomei using both his flail and axe to attack both ends of his neck, it still didn't budge. His neck was only severed thanks to both the combined efforts of both Gyomei and Sanemi putting all of their strength into forcing his neck to be sliced with Gyomei's axe, along with both of their weapons turning bright red, which further hampered his regeneration and durability.
Immense Speed & Reflexes: Kokushibo possessed immense levels of speed, as shown when he outpaced Muichiro's Breathing Techniques with great ease. Muichiro himself stated that Kokushibo's speed was in another dimension compared to the Hashira. Sometimes he could unleash bursts of speeds or sword slashes that evade the senses of both Sanemi Shinazugawa and Gyomei Himejima. He could also move so fast that it made him seem like he teleported, he was able to easily evade the former two Hashira's attacks even when they were marked. He was also able to dismember Akaza's hand when the latter was trying to crush Doma's skull without any of the other Upper Ranks noticing then.
Immense Strength: Kokushibo has displayed incredible physical strength, lifting a gigantic sword that is three times heavier than a regular katana and swinging it incessantly at speeds faster than the eye can see without rest or effort. Since he assimilated more of Muzan Kibutsuji's blood than Upper Rank Three, Akaza, a demon that can create craters in the ground by casually punching it, it can be safely assumed that Kokushibo possessed greater physical strength than him.
Immense Regeneration: Kokushibo possesses one of the most powerful regenerative abilities in existence, second only to the Demon King, Muzan Kibutsuji. His regeneration speed is even faster than Akaza and Doma, re-growing his ear and right arm nonchalantly and effortlessly. Later, upon being decapitated by two marked Hashira, Kokushibo was able to regenerate his entire head and successfully conquered death by beheading after being decapitated by weapons made of Scarlet Crimson Ore, a feat considered impossible for Demons and only accomplished by two other Demons: Akaza and Muzan. Furthermore, he regenerated his head faster and more perfectly than Akaza.
Indomitable Will: Solely because of his goal to surpass his younger twin brother, Yoriichi Tsugikuni, Kokushibo possesses supernatural willpower. When he was about to get killed, he forced his regeneration to evolve, and regrew his own head along with a myriad of enhancements, all because he didn't allow himself to die until he accomplished his goal.
Tactical Intellect: As a talented swordsman who has existed for over four centuries, Kokushibo has experienced countless battle situations and threats which he has learnt to overcome and circumvent. This was displayed during his battle with three Hashira and Genya Shinazugawa, where he was able to adapt to their special and unique fighting styles and tactics nigh instantaneously after witnessing it. For example, after Muichiro Tokito unleashed his first attack against the Upper Rank, he was able to determine he was a user of Mist Breathing, a talented one at that. This was further accentuated through Kokushibo being able to take on Sanemi Shinazugawa and Gyomei Himejima simultaneously despite both of them being marked and being users of different Breathing Styles, meaning he’d have to deal with 2 vastly different opponents at once, which he did so successfully, even overwhelming them multiple times.
Unlimited Stamina & Endurance: Kokushibo possesses absolute and infinite stamina and vitality, never tiring and always remaining in optimal physical and mental condition all the time as well as being able to endure waves of onslaught as if it were nothing. Despite having his ear, then limbs and whole chunks of his body being repeatedly torn off and destroyed, he never once showed a sign of pain or agony. Even when his head was being crushed by Gyomei Himejima's spiked flail, he remained resilient.
Crescent Moon Blades: Complementing his combat style: Moon Breathing, his Blood Demon Art allows him to create and manipulate dozens of sharp blades shaped like a crescent moon from his flesh katana that constantly changes in size, length and speed. This Blood Demon Art results in the enhancement of his techniques, allowing him to overwhelm a marked Hashira, Muichiro Tokito and keep up with two other stronger marked Hashira, Sanemi Shinazugawa and Gyomei Himejima. Since he could generate crescent moon blades from his flesh katana at will, he can create them without swinging his sword as long as it is unsheathed, though he usually creates them when swinging his sword and unleashing Moon Breathing techniques.
Master Swordsman: Due to training and refining his swordsmanship skill for over 400 years and getting a major boost to his physical capabilities, Kokushibo has become the most powerful and skilled swordsman in the modern era, and the second strongest swordsman in existence, behind his younger twin brother, Yoriichi Tsugikuni. With his exceptional sword wielding skill, he could singlehandedly take on Sanemi Shinazugawa, Muichiro Tokito and Gyomei Himejima when they were marked as well as Genya Shinazugawa when he assimilated his blood and gain a small portion of his power.
Moon Breathing (
- First Form: Dark Moon, Evening Palace (
壱ノ 型 闇 月・ 宵の 宮Ichi no kata: Yamidzuki - Yoi no Miya?) - Kokushibo quickly draws his sword and slashes swiftly in a singular horizontal motion in a crescent shape, creating numerous chaotic crescent blades. This technique is extremely reminiscent of Iaijutsu.
- Second Form: Pearl Flower Moongazing (
弐ノ 型 珠 華の 弄 月Ni no kata: Shuka no Rōgetsu?) - Kokushibo performs several crescent-shaped slashes that defend him from incoming attacks, sending a barrage of crescent blades.
- Third Form: Loathsome Moon, Chains (
参ノ 型 厭 忌 月・ 銷り San no kata: Enkidzuki - Tsugari?) - Kokushibo swings his sword rapidly in two gigantic crescent slashes, from which a storm of smaller crescents spread, causing huge destruction in a small area.
- Fifth Form: Moon Spirit Calamitous Eddy (
伍ノ 型 月 魄 災 渦Go no kata: Geppaku Saika?) - Kokushibo makes multiple curved slashes layered over one another, creating a rising vortex of sword slashes and crescent moon blades.
- Sixth Form: Perpetual Night, Lonely Moon - Incessant (
陸ノ 型 常 夜 孤 月・ 無 間Roku no kata: Tokoyo Kogetsu - Muken?) - Kokushibo releases a wild barrage of crescent-shaped slashes several meters in front of him. This technique was powerful enough to overwhelm Sanemi Shinazugawa and so long-ranged that it slices up the surrounding pillars.
- Seventh Form: Mirror of Misfortune, Moonlit (
漆ノ 型 厄 鏡・ 月 映え Shichi no kata: Yakkyō - Dzukibae?) - Kokushibo swings the gigantic version of his sword in a powerful frontal crescent-shaped slash that creates powerful multi-directional long-ranged slashes in the ground.
- Eighth Form: Moon-Dragon Ringtail (
捌ノ 型 月 龍 輪 尾Hachi no kata: Getsuryū Rinbi?) - Kokushibo uses the gigantic version of his sword and creates a singular gigantic crescent-shaped slash that slowly decreases in size, creating dozens of crescent moon blades.
- Ninth Form: Waning Moonswaths (
玖ノ 型 降り 月・ 連 面Ku no kata: Kudaridzuki - Renmen?) - Kokushibo creates a stream of long-ranged crescent-shaped vertical and horizontal slashes along with numerous crescent moon blades with the gigantic version of his sword.
- Tenth Form: Drilling Slashes, Moon Through Bamboo Leaves (
拾ノ 型 穿 面 斬・ 蘿 月Jū no kata: Senmenzan - Ragetsu?) - Kokushibo creates a long-ranged triple-layered slash twister full of crescent moon blades with the gigantic version of his sword.
- Fourteenth Form: Catastrophe, Tenman Crescent Moon (
拾 肆ノ 型 兇 変・ 天 満 繊 月Jū Shi no kata: Kyōhen - Tenman Sengetsu?) - Kokushibo uses the gigantic version of his sword and creates a chaotic vortex of powerful extremely long-ranged omni-directional slashes that destroys whatever is caught up within its attack radius.
- Sixteenth Form: Moonbow, Half Moon (
拾 陸ノ 型 月虹・ 片 割れ 月Jū Roku no kata: Gekkō - Katawaredzuki?) - Kokushibo creates a barrage of downward crescent slashes from an extremely long and wide range, resulting in a powerful six-fold slash crashing down on his opponents; the attack itself is powerful enough to create several miniature craters where the slashes have landed.
- Kokushibo's name contains the kanji for "black" (
黒koku?), "death" ( 死shi?) and "eye" ( 牟bo?).
- He is the older twin brother of the Sun Breathing user who almost killed Muzan, Yoriichi Tsugikuni.
- Kokushibo is presumably the first Demon Slayer to become a demon.
- He became a demon in his early 20s and lived as such for additional 460+ years.
- Kokushibo ranked 14th in the second popularity poll with 2938 votes.
- The relationship between Yoriichi and Michikatsu parallels the mythology of the Shintō deities Amaterasu and Tsukuyomi, respectively. Amaterasu is the most sacred of Shintō deities, the sun goddess. Tsukuyomi, the moon god, is her former husband and brother. After Tsukuyomi killed Uke Mochi, another shintō deity, Amaterasu refused to ever look upon him again, moving to another part of the sky and beginning the cycle of day and night. Like the deities, the siblings also feud and have chosen different paths (that of the Demon Slayer and the demon), developing their respective breathings of the sun and moon.
- (In regards to Akaza) "Akaza's presence is gone. He has fallen. Akaza... weren't you going to defeat me? A path had open for him to attain further heights... but he renounced it himself. How exceedingly weak."
- (To himself) "The old and ugly creature that was once my little brother had pity for me. But... I wasn't angry. Even though 60 years ago, he had been such an eyesore. The voice calling me "brother" was terribly hoarse. My brother had never shown the slightest emotion... so at the sight of him shedding tears, something welled up in me for the first time since birth. I was confused... at my own unexpected unrest. But I must kill... this part of me from when I was human... This old man of brittle flesh past his prime... He was a Demon Slayer, and I must cleave anyone who turns a sword upon me. But his odd sentimentality... disappeared the next moment."
- (In response to Yoriichi Tsugikuni's statement about future generations) "Yoriichi... when you smiled, I couldn't help it... but I always found it disturbing. And when we were talking about how there were no successors for the various breathing techniques you suddenly started viewing things with strange optimism and you smiled. In my conceit I believed that only our generation was special. I felt sick with disgust and irritation. What did you find so amusing? [...] What is so amusing about imaging such a future? Just thinking about losing makes me boil with anger."
- (To himself) "The ugliness of not admitting defeat even though they took my head, chopped me up and crushed me. Living in disgrace. Have I lived hundreds of years for this? Was I so afraid of defeat that I became a monster? Did I want to be strong even if it meant eating people? Did I become this miserable creature because I didn't want to die? No. Yoriichi... I just wanted to be you."
- (To himself) "I could never grab hold of anything. Anything at all. I abandoned my home. I abandoned my wife and children. I abandoned my humanity. I cut down my descendants and abandoned being a samurai. But even all that wasn't enough? You said that those who master their paths all reach the same place. But I never did. I could not see the same world that you did. Why could I not leave anything behind? Why could I not become someone known? Why are we so different? Why in the world was I ever born? Tell me... Yoriichi."