Characters / Demon Slayer: Kimetsu no Yaiba: Kokushibo

Demon Slayer: Kimetsu no Yaiba Main Character Index
Main Characters | Demon Slayer Corps (Hashira) | Demons (Muzan Kibutsuji | Twelve Kizuki: Upper Ranks: Kokushibo | Hantengu) | Civilians | Demon Slayer Academy

Warning: Kokushibo is a Walking Spoiler, so all entries for this character are unmarked.

Kokushibo

Voiced By: Ryōtarō Okiayu (Japanese), Jonah Scott (English) ^{Other VA} Octavio Rojas (Latin American Spanish), Eilias Changuel (French), Frank Schaff (German), Davide Fazio (Italian), Xia Zhishi (Taiwanese Mandarin)

^{Click here to see his former human self}
Michikatsu Tsugikuni, disgraced Demon Slayer of the Golden Era.

"…you suddenly started viewing things with a strange optimism… and you smiled. In my conceit I believed… that our generation was special. I felt sick with disgust and irritation. What did you find so amusing?"

Upper-1. Muzan's partner and right-hand man, he has occupied the position of Upper-1 for at least 400 years. Unlike many other demons, he eschews relying upon his supernatural powers and focuses on perfecting his swordsmanship, the likes of which is unmatched by anyone alive. Because of his rank, he's heavily known as the second strongest demon in the whole series, only next to his master.

As revealed in his backstory though, he is a former Demon Slayer known as Michikatsu Tsugikuni, the older twin brother of Yorichii. Even when becoming the demon, Kokushibo, he still uses a secret derivative of his brother's Sun Breathing known as Moon Breathing.

---

A-K

• The Ace: The top Upper Rank and the scariest, as well as the most skilled. How scary and skilled? His descendant Muichiro is considered The Ace of the Hashira with the most innate potential, and proved it by killing Upper-5 Gyokko after his training to unlock his Demon Slayer Mark easily and by himself, a feat considered nigh-impossible. Kokushibo absolutely thrashes Muichiro in their one-on-one while taking no damage himself. Even if he'll never reach the skill of his younger twin brother, he is a powerful swordsman in his own right.
• Affably Evil: Unlike Akaza, who isn't above trash talking, or Doma, who constantly teases and mocks his opponents, he is very polite and well mannered, as well as sincere, even if he doesn't speak much. He doesn't spare compliments for his opponents either, praising their skill on several occasions. Considering he basically sacrificed his own humanity to conserve and perfect his skills as a swordsman, it makes sense he values and respects dedication to the craft in others.
• Alas, Poor Villain: As he lays dying, he realizes that he ultimately wasted his entire life pursuing an inferiority complex against his brother, even though the latter never bore any grudge against him. His last thoughts are asking why he was even born.
• All for Nothing:
  • Selling his humanity to become the strongest and becoming a monster? He never could surpass Yoriichi and simply becomes one of the monsters that he once hunted. He realized that all of those centuries of trying to be the undefeated swordsman led to nothing beneficial for him.
  • His selfish quest for greatness and the jealous way he guarded the techniques of both his family and those of his own invention ensure that his knowledge dies with them, forgotten and irrelevant.
  • In a twisted case of irony, he initially spares Muichiro's life with the intention of turning him into a demon, as he is pleased that his bloodline lived on even after his transformation. He eventually ends up slaying him later on, ending his bloodline for good.
• Always Second Best: He lived his life in the shadow of his twin Yoriichi. He was never, ever able to surpass him or learn the Sun Breathing. Ironically, even now, he's only the second strongest being, as Muzan is still over him.
• Always Someone Better: For Kokushibo, it was his younger twin brother Yoriichi, who he could never surpass. Even as an immortal demon, and with Yoriichi an old man, Yoriichi still proved to be the superior between them.
• Antiquated Linguistics: He was a human from at least 400 years prior to the current setting. Unsurprisingly, he speaks in extremely antiquated Japanese. How it's translated into English varies within fan translation efforts. The official Viz Media translations put a little more effort into adapting Kokushibo’s manner of speaking from time to time.
• Arc Villain: Alongside Doma and Akaza, he serves as one of the primary antagonists of the Infinity Castle Arc, as well as the Climax Boss of the story arc.
• Arch-Enemy: Twisted all over the place in his relationship with his younger twin brother, Yoriichi Tsugikuni. While Yoriichi always admired his brother and considered him a good person, Kokushibo was extremely jealous of Yoriichi's natural talent, which he could never measure up to despite endlessly training, and a significant portion of his motivations centers entirely around his inferiority complex regarding his brother. He insists to himself that he thoroughly detested Yoriichi, including but not limited to describing himself as "blazing with hatred" for him and mentally begging him to die. However, it's clear that this is a case of an Unreliable Narrator (regarding his own backstory, no less). In spite of his envy for Yoriichi, Kokushibo loved his brother deeply, shedding tears over his death and moved by the realization that Yoriichi had kept the flute that he gave him when they were children and continued thinking highly of him even after he became a demon. After Yoriichi's death, he was unable to part with the flute and kept it on his person until his own demise several centuries later. Furthermore, it is remembering Yoriichi's words to him that made Kokushibo falter upon realizing how hideous he'd become in his pursuit of strength, and the last person he calls out to as he disintegrates his brother, asking him why he was ever born, of all things.
• Awesomeness by Analysis: A shared trait with his younger twin, Kokushibo has nurtured centuries of his Transparent World proficiency, and six eyes as a demon, to become able to instantly analyze the physique of any foe that catches his attention down to their very cells; Kokushibo could immediately tell Muichiro was his descendant by seeing through his genetic code, and was able to proclaim Gyomei was a singularity among any of the Hashira he has ever faced, by seeing through every bone and muscle fiber of Gyomei’s body.
• Baritone of Strength: The second strongest demon and a Master Swordsman has a deep voice to go with it.
• Beta Test Baddie: Kokushibo's motivation to become the best swordsman is driven by his inferiority complex that stemmed from his brother Yoriichi always being better than him.
• BFS: It turns out his regenerating katana can grow longer and sprout multiple smaller blades out of its main blade. It also counts as an Oddly Shaped Sword due to adding extra blades on its blade.
• Big Brother Worship: Inverted. In his final moments, he remembers that all he wanted was to be like his younger twin brother, Yoriichi. Ironically, Yoriichi has this toward him as well, deeply respecting and loving his older brother even after he chose to become a demon.
• Body Horror: His monstrous spider-like form in chapter 176 is shown to be very disfigured. His head has all six of his eyes staring in all directions, and he grew a snout full of sharp and crooked teeth sprouting everywhere. Upon seeing his reflection on Sanemi's blade, even he is disgusted by this form.
• Broken Ace: Despite his strength and talent, he was always surpassed by his younger twin brother and because of that, it caused him to become envious and jealous towards him and besides that, he feared the possibility of defeat and death, so he went as far to become a demon to avoid that. Despite this, he nearly gets killed by Yorrichi who was a dying elderly man. The fact Yoriichi dies of old age instead of dying in battle enraged Kokushibo since that makes Yorrichi an undefeatable warrior, something that Kokushibo wanted to become. But now with Yoriichi dead, Kokushibo's pitiful inferiority complex continues to worsen for him.
• Cain and Abel: Chapter 174 reveals that he is the eldest twin brother to Yoriichi Tsugikuni, the Sun Breathing user. He became jealous of Yoriichi because he had much greater natural talent and skill than he could ever compete with, even though he was taught daily in swordsmanship while Yoriichi had not trained a day. He was even astonished that his brother managed to survive with a Demon Slayer Mark during their battle 400 years ago and that even at the age of 85, Yoriichi's skill and physical prowess hadn't dulled in the slightest.
• Climax Boss: The showdown with him reveals key elements of the series lore, and it also marks the ending of the Twelve Kizuki, who had been the most prominent antagonist up to that point. Suitably, once Kokushibo is defeated, Muzan himself takes center stage.
• Clipped-Wing Angel: What his spider demon form turns out to be. His frustration at his brother's beliefs and the strength of the Demon Slayers gives him the determination to not lose, forcing himself to regenerate despite being beheaded like Akaza. However, unlike Akaza's subconscious drive to protect his loved ones, Kokushibo's determination is fueled by a combination of jealously, obsession and desire to avoid death, so this ends up being a highly unstable, monstrous spider-like form. On top of this, it took a lot of energy for him to No-Sell his beheading and his regeneration slowed down considerably as a result. Kokushibo’s grotesque appearance also leads to the demon having a What Have I Become? moment when he sees his reflection, and his drive to fight dies off.
• Clothing Damage: He loses his haori to Himejima and Sanemi's combination attack, leaving him topless.
• The Coats Are Off: He already seemed to be too much trouble with his clothes fully on. Kokushibo was making three Hashiras (Muichiro, Himejima, and Sanemi) break a sweat against him. Then, Himejima and Sanemi manage to rip Kokushibo's haori (coat) off, and that's where Kokushibo stops playing around. Himejima and Sanemi went from trying to go on the offensive to then struggling just to not die against Kokushibo's devastating long-range attacks.
• Combat Compliment: In the same vein as Akaza, Kokushibo respects strength in others, he is more polite and composed about it though, to him it is more about noticing how much effort one has put into disciplining themselves in martial arts than loving how good the slayers are doing against him.
• The Corrupter: Kokushibo converts Demon Slayers over to Muzan's side by overwhelming them with his power and then forcing them to drink Muzan's blood, turning them into demons themselves. He recruited Kaigaku this way and would have done the same to Muichiro if Genya and Sanemi haven't intervened.
• The Corruptible: Although he converts humans into demons, he himself was a victim of this by Muzan who preyed on his insecurities to convince him to become a demon.
• Curb-Stomp Battle: He absolutely dominates his descendant Muichiro in their one-on-one fight, overwhelming him even better than how Muichiro in turn had managed curb-stomp Gyokko in their own rematch.
• Death Glare: He gives an epic one when he wishes to make a point. When you have six eyes, it's easy to be intimidating.
• Deconstructed Character Archetype: Kokushibo deconstructs the Green-Eyed Monster trope: He was so envious that he is, and always will second best to his younger twin Yoriichi that he abandoned his family then joined Muzan's forces to live forever and gain more power, and even then, he was still no match. Ultimately, that achieves nothing but ensure his own death in the final showdown, and Kokushibo even starts questioning if it was all worth it shortly before he's dispatched.
• Despair Event Horizon: He gave in to total despair, realizing his Mark would kill him, and he'd never be able to grow beyond Yoriichi. Muzan takes full advantage of this and easily convinces him to become the demon Kokushibo.
• Determinator: All through his life as both a human and demon, Kokushibo gave his training and swordsmanship everything he had. He doesn't go down easily and even wills his head to regenerate after being decapitated.
• Disappeared Dad: He is one, Kokushibo doesn’t mince words when recalling his past life as the human Michikatsu, at the time he was seemingly the happiest as the head of the Tsugikuni family with a wife and children to care for, but upon unexpectedly reuniting with Yoriichi after so many years, upon being saved by Yoriichi in a losing battle against demons no less, reignited his desire to grow stronger as a warrior; with that Michikatsu simply abandoned his family to pursue strength for himself, a fact that only got worse after he betrayed the Demon Slayer Corps to serve Muzan as the demon Kokushibo; that little unexplored fact certainly destroyed the Tsugikuni family over the centuries, seeing how his known descendants were just a poor family of lumberjacks living in the mountains, compared to another prestigious family from the Golden Age of Demon Slayers, the Rengoku family, remaining intact in their notoriety.
• The Dragon: As Upper-1, Kobushibo is Muzan’s right-hand man and their relationship is more business-like. He’s also the second strongest demon in the series.
• The Dreaded: As the second strongest demon, his power and aura is so terrifying that it would even make the other Upper Ranks tremble in fear. When first meeting him, Muichiro Tokito, a Hashira who had faced an Upper Rank on his own in the past and won, was shaking with fear, to the point of even nearly losing his will to fight against Kokushibo.
• Driven by Envy: In his jealousy over his brother's unmatched natural talent, Kokushibo became a demon to perfect his swordsmanship and even faced off with Yoriichi in a duel. Yoriichi managed to slash Kokushibo but old age got to him and he died midway.
• Dying Alone: Upon death Kokushibo shamefully joins the ranks of demons who have died without anyone being there for him in the afterlife, the sign of karma for abandoning everyone that had cared for him; Kokushibo is seen being forcefully dragged into hell alone on Chapter 179's cover page.
• Even Evil Has Loved Ones: A powerful and ruthless demon, but he still remembers his human children very fondly and is pleased to learn his family's bloodline eventually produced another Master Swordsman in Muichiro. And although he hated his brother Yoriichi, he still had a complicated sense of brotherly love for him. Additionally, part of his hatred for Yorichii is more of a fabrication by himself, as Yorichii's own backstory directly mentions that Michikatsu was never mean or unfriendly to him.
• Even Evil Has Standards:
  • As the highest ranked demon in the Twelve Kizuki, he doesn’t tolerate any kind of insubordination and petty grudges among his fellow demons. In the Upper Ranks gathering, when Akaza attacks Doma violently when he was telling Gyokko to tell him the information he gathered for Muzan, Kokushibo immediately bisects Akaza’s arm as punishment for his disobedience, arguing that if he doesn’t like his situation, he should challenge him and Doma to a duel to prove if he’s worth of ranking higher than them, prompting the normally impulsive Akaza to back off.
  • Despite bisecting Akaza's arm after attacking Doma, he makes it clear to Doma he wasn't doing it for his benefit, showing that just like the rest of the Upper Ranks, he doesn't like him at all.
• Evil Counterpart: To Gyomei. They are both the strongest members of their respective groups, Gyomei as the strongest of the Hashira and Kokushibo as the strongest of the Twelve Kizuki. They were even on par with each other during their fight.
• Evil Is Petty: Despite his stoic and phlegmatic personality, he does taunt Sanemi and Himejima when they rip off his kimono, calling it a move that wouldn't even kill an infant.
• Evil Sounds Deep: As portrayed by Ryōtarō Okiayu and Jonah Scott, Kokushibo speaks with a menacing baritone fitting of his status as the deadliest of the Twelve Kizuki.
• Evil Twin: He's the oldest twin brother of Yoriichi Tsugikuni, and is the second strongest demon in the series.
• Evil Virtues: Kokushibo seems to possess a few such as:
  • Respect. Despite being a highly powerful demon, second only to his master, Kokushibo doesn't completely look down on humans, having a slight degree of respect for them (as far as wanting them to become demons, however, as seen with Muichiro). For example, he respected Muichiro, Genya, Sanemi, and Gyomei for their skills and strength. And despite his annoyance of Akaza, he had a great deal of respect towards him.
  • Loyalty. Kokushibo is completely loyal to Muzan, carrying out his duties solely to serve his master's ambitions. While Kokushibo has ambitions of his own, he's willing to help his master achieve his.
  • Determination. Kokushibo is determined to win and he will not go down easily. Even after being decapitated, he used his sheer will to completely regenerate his head to conquer death. If he didn't see what he became, he wouldn't lose his will to fight.
• Exotic Eye Designs: His rank is his central pair of eyes and all others have very prominent veins and crimson sclera.
• Explain, Explain... Oh, Crap!: After his mother's death, he reads about her condition, and discovers a surprising truth- she had difficulties with the left side of her body. He then repeats what he'd just learned twice before the truth dawns on him - Yoriichi hadn't been clinging to his mother; he'd been supporting her, having noticed how her illness had weakened her.
• Extra Eyes: He has six.
• Eyes Do Not Belong There: His katana has over a dozen eyeballs on the handle, And the blade has even more.
• Fallen Hero: He was a Breathing user turned demon because he feared the loss of all of his techniques at age 25, due to the dangerous conditions of the Demon Slayer Mark.
• Family Man: Used to be one. He had a wife and two kids whom he seemingly loved and lived with peacefully.
• Fatal Flaw: Envy. His extreme jealousy of Yoriichi's natural talent led to a lot of things falling apart in his life: he abandoned his wife and kids, he became susceptible to Muzan's manipulations and got turned into a demon, which ultimately leads to his demise in the final battle.
• Fights Like a Normal: Despite being a demon, Kokushibo relies more on his swordsmanship and Moon Breathing techniques, rather than using the supernatural Blood Demon Arts.
• Flash Step: Fast enough that nearly all of his movements appear this way. Only fighters as experienced as Himejina and Sanemi can (somewhat) keep track of him, much less even attempt to attack him.
• The Fog of Ages: He is one of the few demons who remembers the events of his human life clearly, but has been alive for so long that he has forgotten the faces of his parents, wife, and children. The only person whose face he remembers vividly is his brother Yoriichi.
• Foil:
  • Is ultimately one to his younger twin brother, Yoriichi. Yoriichi was a human with extraordinary swordmanship and had the most powerful breathing style that could even slain down Muzan, while Kokushibo was originally a human being who was the second strongest being behind Yoriichi, and even now, still is the second strongest demon behind Muzan. The difference in that is that Yorrichi was an extremely kind and gentle soul who was always respectful and humble towards others, never looking down upon them, while Kokushibo was an extremely envious and spiteful person towards his younger twin brother and was incredibly selfish, willing to go extreme lengths in order to never lose a battle nor his techniques, even going so far as to eventually becoming a demon.
  • Also acts as one to Genya. In addition to the visual similarities (facial scars, spiky hair, and purple-and-black clothes), Genya is a human who uses demon arts, while Kokushibo is a demon who uses a breathing style. Both resorted to using the power of demons to become stronger than their more-skilled brothers, and both use nonstandard weaponry for their respective roles. They differ in that Genya is a Jerk with a Heart of Gold while Kokushibo is Affably Evil, and while both sought to become as strong as their brothers, Genya never went as far as to ally with Muzan himself, or even to the extent of feeling envy towards Sanemi. In the end, they die similar deaths, but while Kokushibo falls in utter despair, desperately wishing he could talk to Yoriichi one last time, Genya is able to reconcile with Sanemi in his final moments, his last words being a heartfelt Dying Declaration of Love.
• Green-Eyed Monster: Kokushibo's driving motivation besides his fear of losing his skill to aging and death was deep envy of his twin brother Yoriichi, particularly Yoriichi's great skill and selfless devotion to others.
• Glass Cannon: Kokushibo is lightning fast, on top of being a Master Swordsman with a Blood Demon Art that can massively extend and alter the range of his katana. But because his fighting style is so mobility-oriented, Himejima and Sanemi quickly start gaining ground after Genya manages to root him to one spot with his Green Thumb ability.
• Happily Married: As a human, he had a wife and two children who he is seen happily smiling with in a flashback, a period of his life he described as very peaceful. This was shattered the moment he reunited with Yoriichi, feeling all the hatred and resentment he had as a child come rushing back. Soon after, he abandoned his family to follow Yoriichi in search of greater strength.
• Hard Work Hardly Works: One of the major sources of his angst is the fact that, no matter how much effort he puts, he was never able to prove himself to be equal, let alone surpass, his younger brother Yorichii, who was born with a natural talent. No matter how much Michikatsu worked and trained, he was not only unable to defeat his father's servant while Yorichii was able to win effortlessly, but he was also never able to learn the Sun Breathing in spite of his best efforts, instead learning only the mere derivative called the Moon Breathing, and that no matter what he did, Yorichii always proved himself to be much more powerful and talented swordsman, even though everyone else, Michikatsu included, worked diligently to try to keep up with him.
• Healing Factor: Like all Demons but Kokushibo stands out because his katana also has the ability to regenerate, able to grow back its blade if snapped or even reform entirely from Kokushibo's flesh if completely destroyed.
• Heel Realization: When he looks at his own reflection in Sanemi’s sword, he realizes what a monster he's become, despite trying to retain his human appearance. He decides to die in shame of turning into such a beast.
• Hero Killer:
  • According to supplementary material, after his brother had died, Kokushibo discovered the residence of the Ubuyashiki family and killed the leader of the Demon Slayer Corps at the time, bringing his head to Muzan. This severely weakened the Corps and led to a period where they were thought to be wiped out, but in truth the surviving Ubuyashiki family members had gone into hiding and began implementing the vast security measures and secrecy that they still employ in the present.
  • He takes the lives of both Muichiro and Genya during the course of their battle.
• His Own Worst Enemy: The tragedy in his human life comes from a succession of choices he made and had no one else to blame but himself, unlike several of his fellow Kizuki members who suffered under completely external factors. Michikatsu chose to harbor jealousy over Yoriichi's talent which nurtured a massive inferiority complex, to the point he created his own false memories of absolutely hating Yoriichi over the centuries in order to force himself to believe his choices were valid, not petty; Michikatsu chose to abandon the life as the head of the Tsugikuni family, leaving his wife and children behind to pursue strength under Yoriichi's teachings; Michikatsu chose to betray the Demon Slayer Corps with the growing fear of dying under the effects of the Mark and wasting all the years he gave into perfecting his martial arts, turning into the demon Kokushibo to retain all of it. As Kokushibo is about to die he is left with nothing but regrets, coming to terms all of his efforts to remain alive as a demon led to absolutely nothing truly beneficial to him, and he just couldn't hate Yoriichi as much as he believed he did, wondering why he was even born.
• I Just Want to Be Special: He reveals that his entire motivation and reason for jealousy was because he wanted to be special like his brother Yorichii was in the past. Or at least he conceptualized that on a surface level, as he actually had a complicated sense of love for Yoriichi and during most of their childhood what Michikatsu wanted was simply a brother on equal terms. Yorichii could never provide that and this emotional loneliness slowly poisoned his psyche.
• Implausible Fencing Powers: is Blood Demon Art is not only the manipulation of his sword to grow or sprout additional blades but also to grow dozens of blades out from various points in his body, allowing him to use his Moon Breathing techniques with all his blades at once. Keep in mind, they're still in his body and poking out from spots like his thighs, his chest, his shoulders, etc.
• Irony:
  • Muzan's greatest servant and one of the most dangerous Kizuki to ever live was a Slayer in his human life, and is implied to have secured his status as such using the Demon Slayer Mark and Transparent World technique he originally mastered for the sake of hunting demons.
  • For all he resented Yoriichi for having everything he wanted, it's later revealed that Michikatsu had something Yoriichi wanted just as much; a quiet, happy life with his wife and child.
  • He was never able to shed his last vestige of humanity and love for Yoriichi, even as he laid dying. In turn, Yorichii himself was able to abandon his love for Michikatsu when he finally decided to put him down for all the atrocities he commited as a demon (No matter how it pained him to do so).
  • As mentioned in All for Nothing entry, his desire to become special by guarding and hoarding all his secrets and the techniques he learned and developed ended up being forgotten and irrelevant, which was basically against to someone who wants to get recognized.
  • Also, as mentioned in Always Second Best, Kokushibo was always envious towards Yoriichi because of the fact that no matter how much he trained, he could never reach Yoriichi. As the Upper Moon 1, Kokushibo will eternally always be second best to the demon king, Muzan.
• It's All About Me: His motivation in his human days as Michikatsu was to be the best and undefeated swordsman in all of Japan. And he was willing to go great lengths in order to never to lose a battle nor his techniques, so far as to eventually becoming a demon. He also lost hope of training the disciples who could not successfully master the Breathing techniques under him and his brother Yorichii and decided to not pass down the teachings, keeping the techniques to himself. Yorichii thought differently, though; He believed that the next generation of swordsmen would one day surpass both of them in the future. Michikatsu was only thinking about himself, so of course, he could not comprehend the hope Yorichii had for the next generation.
• Intoxication Ensues: Sanemi attempts to throw off Kokushibo's game by using his rare blood to intoxicate the air. It works since Kokushibo smelled his blood and started stuttering with his footwork, but this was only temporary, as Kokushibo eventually regains his focus.
• Katanas Are Just Better: He's the only demon in the series who wields a katana. This is because he used to be a Breathing User.
• Knight of Cerebus: His every appearance is framed so as to inspire dread from both the audience and the Demon Slayers that face him.

L-X

• Lonely at the Top: Kokushibo went as far as to become a demon in his relentless pursuit of being World's Strongest Man, but it came at the cost of losing the relationship with his wife, children, and brother.
• Luke, I Am Your Father: Or ancestor to be exact, towards Muichiro.
• Lying to Protect Your Feelings: Essentially did this to himself. He's spend a good part of his life relentlessly telling himself that he hates his twin Yorichii down to his core. In truth he has a complicated sense of brotherly love for him and he greatly mourns his passing, not to mention he still keeps a memento of him well over 300 years after he died. He does this because accepting it would mean that half of his reason for becoming a demon and sacrificing everything to preserve and perfect his craft was a complete waste of time that he didn't even truly wanted to do. The moment he comes to terms with the fact that he lived out of jealousy and a rivalry he didn't truly believe in he asks himself what was even his worth in life and he stands still as the demon slayers maul him to death.
• Magic Knight: He's the second Breath User to generate magic elements from his fighting style. Kaigaku was the first to use actual electricity in his sword, while Kokushibo generates crescent moon-shaped blades from his sword.
• Married to the Job: He used to be Happily Married as human with a wife and his own kids. However, once his obsession with surpassing his brother Yoriichi started to manifest, Kokushibo abandoned them in favor of honing his swordsmanship.
• Master Swordsman: In terms of pure skill, there is no swordsman alive, human or demon, that can match Kokushibo. It took two Hashira and a Demon Slayer able to steal Blood Demon Arts to keep pace with him in combat. He'd be the uncontested World's Best Warrior if not for his brother Yorichii, which has left Kokushibo with... issues.
• Mirror Character: Despite the animosity between him and Akaza, the two are more alike than they realize compared to the rest of their peers in the Upper Ranks. They are both the Token Good Teammate to a certain degree thanks to being Affably Evil towards humans with a tragic backstory involving their loved ones and they both Used to Be a Sweet Kid.
• Monstrous Cannibalism: According to the 2nd Databook he has consumed other demons in a display of utter dominance over those below him, particularly doing so against demons who tried to challenge him for his Upper Rank 1 spot; the only one whom Kokushibo hasn’t eaten after daring to fight him is Akaza, Kokushibo really held high hopes for the Upper-3 to become a suitable rival towards him, allowing Akaza to challenge him several times throughout the years.
• Motivated by Fear: As much of an unparalleled image of a Samurai of the Sengoku Period he held onto for over 400 years, back in his days as a human Kokushibo was actually consumed by the growing fear of potentially dying over the observed effects of the Demon Slayer Mark when he was the demon slayer known as Michikatsu Tsugikuni; Kokushibo’s attachment to the martial arts he worked so much to perfect outweighted the pride and honor many demon slayers are shown to have, those who would rather die as a human fighting demons to the death rather than bowing down to Muzan and become a demon.
• Multi-Directional Barrage: Kokushibo is capable of covering a very wide range around his body with his BFS and Moon Breathing techniques, making him nearly untouchable when he gets serious. He is able to completely overwhelm Gyomei and Sanemi this way.
• My God, What Have I Done?: He got his head chopped off but managed to hold on and even regenerate his head back. Then he saw a reflection of himself on his enemy's blade, of how hideous a form he had taken, how low he had fallen, just to be the strongest, and started to question if this was what he wanted. And with that, his regeneration was negated by the crimson Nichirin Blades, and he crumbled.
• Names to Run Away from Really Fast:
  • Kokushibo derives his name from the Japanese word for The Black Death. He is one of the few demons who clearly remembers their past lives as human beings, including their previous name, Michikatsu Tsugikuni, so it seems he willingly took that name.
  • The name he gave his sword, as revealed in the data books Kyokokukamusari, which translates to 'Hollow Cry of the Godless' also qualifies.
• Noble Top Enforcer: While his master, Muzan Kibutsuji is a petty, sadistic, and sociopathic demon, who commits a lot of cruel actions with no sense of remorse and looks down on humans, seeing them as weaklings, his right-hand man is different. Kokushibo is a noble and respectful demon, who has a slight degree of respect towards humans. He also doesn't really take pleasure in the evil actions he commits and isn't really sadistic as his fellow Kizuki demons (With some exception of Akaza). While he's not a complete saint, he's definitely not as bad as his master.
• No Brows: Since he has Extra Eyes both above and under his face's main pair, it cancels out any eyebrows, which adds to his already stoic appearance.
• No-Nonsense Nemesis: Kokushibo does not screw around. When a fight starts and his sword is drawn, he aims to bring his opponent down and break them completely. The most he'll allow is for a defeated foe to become a demon themselves.
• Not So Stoic:
  • Kokushibo, when pressed, begins shedding his stoicism, letting loose ear-splitting roars of fury.
  • There's also regarding his brother, Yoriichi. In the past, Kokushibo showed great signs of anger and jealousy towards him due to Yoriichi being better than he was.
• Numerological Motif: He has six eyes, wears a haori patterned with hexagons colored with the sixth color of the rainbow, and is the last and thus sixth member of the original Upper Moons to fall. The number six also commonly represents falling short of divine perfection, which is an apt description of his relationship to Yoriichi.
• Parental Abandonment: In his past as a human, he left behind his children to join the Demon Slayers in the hope of surpassing his brother Yoriichi.
• Perpetual Frowner: The only times he cracks a smile is when he's a child. Other than that, he doesn't crack a smile at least once.
• Polite Villains, Rude Heroes: The polite villain to Sanemi's rude hero.
• Power Tattoo: The markings on his face are a Demon Slayer Mark, which increases a Demon Slayer's strength, durability, and speed to legendary heights. He became a Demon in order to prevent the Mark from killing him at age 25.
• Purple Is Powerful: Kokushibo wears a distinct purple haori and is the most powerful Upper Rank by a significant margin.
• Razor-Sharp Hand: When Muichiro impales him and refuses to let go of the blade despite being in pieces, Kokushibo severs Muichiro's remaining arm clean off with a chop from his bare hand.
• Red Eyes, Take Warning: The sclera and all six of his eyes are dark red with a citrus-like vein pattern, and he's the most powerful of the 12 Kizuki, and the second most powerful demon overall.
• Removed Achilles' Heel: Just like Akaza, he manages to overcome decapitation with sheer willpower. Unfortunately for him, he's too weakened from all the wounds already inflicted, and he's still vulnerable to the Crimson Nichirin blades, allowing Sanemi and Himejima to kill him by just wailing on his body until there was nothing left. He could have probably still have kept up fighting, but seeing his own hideous reflection caused him to loose his drive and he stood still, letting himself get finished off.
• The Resenter: Towards Yoriichi, of course. However, he still had complicated feelings of brotherly love for him in the end, and had always been nice with him despite Kokushibo himself stating otherwise.
• Secret Art: He doesn't use Blood Demon Arts as his primary method of fighting. He's a Breathing user; specifically, Moon Breathing. For him, his Blood Demon Arts are his Secret Art.
• Sibling Yin-Yang: He and his twin brother Yoriichi. While he fears death because he's afraid that his sword techniques will be lost, his brother accepted this, believing that someday someone stronger than him will surface and surpass them. He is the user of Moon Breathing, while his brother is the user of Sun Breathing.
• Simple, yet Awesome: His Blood Demon Art is the ability to sprout swords from his body, nothing too spectacular next to the other Twelve Kizuki. Yet it's effectiveness can't be denied since it means he'll never be disarmed, he can change the shape of his sword to boost his technique's power and range, and he can sprout and shoot out swords all over his body and use techniques from every one of them.
• Sizeshifter: During his battle with the Hashiras, he slowly becomes more muscular and taller after they destroy his haori, eventually standing head and shoulders above even Himejima.
• Speak Ill of the Dead: After he senses Akaza's death, he scoffs that Akaza did not make good on his promise it fight and kill him, and that after all he had and could accomplish, he ultimately ended his own life.
  "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."
• Spiky Hair: A more subdued example than most, but his Samurai Ponytail and bangs are spiked, adding to his already intimidating appearance. This contrasts with his brother's free-flowing hair and made a notable distinction between the otherwise identical twins when he was still human.
• Solar and Lunar: Michikatsu Tsugikuni, great demon slayer of the Sengoku Period, eventually betrays his own humanity and becomes a demon, all for the increasing jealousy he held over his twin brother Yoriichi Tsugikuni for being so incredibly strong to the point Michikatsu thought it was simply unfair to never be comparable to his own younger twin, that reflects on his sword style, called Moon Breathing, being in the shadow of Yoriichi’s Sun Breathing.
• Start of Darkness: In chapter 177's flashback, Michikatsu reads his mother's will and after finding out that Yoriichi knew about their mother's sickness and had been helping her out rather than clinging to her side like he thought, his nose bleeds and he starts to feel jealousy against Yoriichi because he gained their mother's affection and Yoriichi had always been talented since birth.
• The Stoic: Nothing phases him at all. Not death threats from a subordinate, not Muzan contemplating exterminating the Twelve Kizuki, not a death battle. But when it comes to Yoriichi or when he gets too pressed in battle, that's a different story.
• Straight Edge Evil: In order to show how much Kokushibo forsaking his humanity was a complete conscious choice to preserve what he most cherished as a human: martial arts prowess, Kokushibo's personality and conduct essentially remained the same even as he reversed roles, simply changing from once hunting demons to preserve humanity, to preying on humans to preserve his demonic self. To note, he essentially became an evil samurai: Kokushibo is strictly loyal to Muzan not out of shared ideals or sadistic commonality, but simply due Muzan being his demon lord and so whatever his master says, goes; Kokushibo remains focused on perfecting his swordsmanship just as he did as a human, but as a demon he has all the time in the world to do so without aging. That's why his death ended up being such a dark realization, Kokushibo knows he betrayed his companions and humanity for a prolonged life where he consciously corrupted everything he had, becoming a human-devouring monster, for a long life that brought no real benefits at all since the swordsmanship he held dear died with him, leaving nothing behind.
• Super-Scream: During his final stand he unleashes shockwave-like roars to great effect.
• Super Mode: His fear that he might actually die against the Hashira causes him to unleash his Blood Art to his full power, which sprouts copies of his sword from numerous points over his body. This allows him to use his Moon Breathing technique with each one of the swords at once, meaning that if he hadn't been restrained and weakened by Genya's Blood Art, he would have easily killed the Hashiras that were struggling to contend with him when he had just one sword.
• Super-Speed: He tends to move around using the Flash Step, and he's so fast that other Upper Ranks and Hashira can't track his movements.
• Sword Beam: He can create large beams from his sword when his sword enlarges. It greatly increases his range and puts Himejima and Sanemi on the defense.
• This Cannot Be!: Other than his existencial regrets over abandoning his humanity not granting the feeling of superiority Kokushibo craved over his younger brother Yoriichi, he dies also questioning how Tanjiro knows Sun Breathing at all since he and Muzan went to through great lengths to personally kill every single disciple of said style over the years before and after Yoriichi's passing. Kokushibo and Muzan didn't know Sun Breathing was secretly, and somewhat accidentally, preserved by the Kamado family who wished Yoriichi had a legacy to leave behind; when Muzan killed Tanjiro's family he actually had no idea they had anything to do with Sun Breathing, he was just trying to experiment if new useful demons could be born there.
• Token Good Teammate: Severely downplayed; he shares this spot with Akaza, as they are the only two surviving members of the Kizuki (excluding Gyutaro, Daki, and Rui) with genuinely tragic backstories and a certain degree of respect for humans.
• Tragic Keepsake: As a child, he gave his younger brother a crude wooden flute that Yoriichi came to cherish as his most precious possession. After they have their final duel and Yoriichi passes on, Kokushibo finds that Yoriichi had kept the flute on his body all that time despite knowing his brother had forsaken his humanity and become a demon, something which deeply moves Kokushibo and brings him to tears. After his death at the hands of Gyomei and Sanemi, it is revealed that Kokushibo kept the flute on his body as Yoriichi had, the last remnant of his humanity that he could not let go of.
• Undying Loyalty: Kokushibo serves Muzan as a samurai would serve his chosen lord.
• Unknown Rival: Played for Drama. Despite Kokushibo's intense resentment towards Yorichii, the latter never noticed it, always thinking highly of his older brother despite being more powerful. It ironically drove a further wedge in their relationship.
• Unreliable Narrator: To his own backstory no less. By his own admission, he hated Yorichii's guts since they were little kids. Oddly enough, all of his actions towards Yorichii when they were children are very kind and friendly, to the point Michikatsu was willing to endure beatings from their father for the chance to give toys and play with Yorichii. Further proven when Michikatsu is seen from Yorichii's perspective in his own backstory. Yorichii has nothing but kind words about Michikatsu. Considering Kokushibo's reaction when Yorichii passed away, it comes off more as a desperate attempt to convince himself that he had no love for his brother.
• Used to Be a Sweet Kid: When he was Michikatsu in his youth, he wasn't really outgoing, but he was not bad either. This was due to how he was raised by his father, who was a strict man who separated the twins. One of the kind gestures that he had done as a child was giving his little brother Yoriichi a small flute he made himself. Kokushibo's current feelings about this are mixed, but Yorichii's flashback proves that back then Michikatsu simply liked his brother and wanted to play and be with him.
• Villainous Breakdown: Not as much as most other examples, but as the slayers start gaining ground on him and getting closer to victory, he starts panicking and loses his composure.
• Villainous BSoD: He finally realizes his monstrosity when he sees his reflection in his final battle, resulting in him letting the Hashira cut him apart.
• Villain Has a Point: For all of Yoriichi's speeches about how the future generations could surpass them and that they were nothing but common men, Kokushibo's worry about the lost of skill with their deaths ended up being partially right. No swordsman ever after Yorichii has ever come remotely close to his level of skill, and Kokushibo himself remained as the greatest living swordsman, eclipsing even the likes of Himejima by a large margin; however, Yoriichi was indeed right about Sun Breathing eventually being passed down, it was the Kamado family that truly inherited its legacy and preserved it for centuries, even if no other swordsman as skilled and powerful as Yoriichi was born from it.
• Villain Respect:
  • In the Upper Moons meeting, he can only respond to Muzan's enraged question about why the Ubuyashiki family isn't eradicated yet by admitting that Kagaya is a master at disguising himself.
  • After discovering that Muichiro is his direct descendant and analyzing his fighting skills, he gives him great respect and even offers him to become a demon and join Muzan's army if Muzan allows it. But he gives the greatest respect to Himejima, who he claims is the strongest Hashira he has fought in over 300 years, and attempts multiple times to persuade Himejima to become a Demon so that he can preserve his techniques since the Demon Slayer Mark will kill him by the end of the night.
  • In addition, according to the official fan book, when asked about his opinion on Himejima the Demon Slayer that helped kill him, he responded with "He resembled the benevolent kings."
• Walking Spoiler: As can be told the spoilers being unmarked, it's hard to discuss Kokushibo without delving into the deeper lore of the series or mentioning the consequences of his battle with the Demon Slayers. Even the most basic aspects of his character, such as his appearance and fighting style, can be considered hefty spoilers.
• Was It Really Worth It?: His final moments has him seeing just what became of him because of his jealousy of Yoriichi, and question whether it's really what he wanted or not.
• What Have I Become?: Seeing his spider demon form reflected in Sanemi's sword makes him realize how much of a monster he has become in trying to be as strong as his talented brother. Understanding how much shame he has lived with through his life just because he couldn't stand losing to his brother causes his regeneration to give out to the wounds of the new Crimson Nichirin blades wielded by the Hashira, and he stands still allowing Sanemi and Himejima to smash him to bits.
• The Worf Effect: He is nearly decapitated by an 80 year old Yoriichi in a single slash just to showcase how absolutely powerful his brother is, even as an elderly man.
• World's Strongest Man: As the holder of the title Upper-Rank One, Kokushibo is as powerful as a demon can possibly become without occupying Muzan's unique position as the Monster Progenitor. And thus stronger then every other fighter in the setting excluding his brother. It says something that Muzan of all people considers him more a partner than a subordinate. In addition to being amped up on the flesh and blood of innumerable humans over the years, Kokushibo is a Master Swordsman whose been practicing his own unique and highly advanced Breathing Form for 300 years. During his final battle, it takes the combined efforts of three Hashira, two of which are considered the strongest and one of which has the highest potential for growth, with the Demon Slayer Mark and a slayer that had stolen the powers of two of his fellow Upper Ranks to bring him down, and even then he only lost because he got distracted by an existential crisis.
• X-Ray Vision: His six eyes allow him to see through his opponent, being able to examine their inner body structures and such.
• You Remind Me of X: Upon encountering Muichiro, he tells him that he seems quite familiar. Muichiro is his descendant, meaning that he is his direct ancestor.

---

"Why in the world was I ever born? Tell me, Yoriichi."

---