Please note that this content contains spoilers from the Demon Slayer manga.
Invariably, when a shonen anime amasses a sizable fan base, discussions about power rankings and hypothetical battles swiftly emerge, and Demon Slayer is no different. Enthusiasts often engage in debates regarding the outcome of intense clashes among characters. Amid these debates, Kokushibō garners substantial attention due to his distinct array of abilities.
Kokushibō makes his prominent appearance in the manga's 99th chapter and episode 45 of the anime, aptly named "Someone's Dream." Within the narrative, he belongs to the Twelve Kizuki, an assembly housing the world's most formidable demons. Elevated to the Upper 1 rank, Kokushibō stands as the mightiest demon within this already formidable faction, second in potency solely to Muzan Kibutsuji, the demon king.
Kokushibō's Many Skills
One of the most dangerous things about Kokushibō is his skill with a sword. He can easily slice through even the most talented foes and seems to be able to constantly swing without showing signs of fatigue. He also has many demon abilities, including Flesh Manipulation, which lets him alter his appearance and body shape. Kokushibō uses this ability to create a weapon out of his own flesh. This flesh katana is amazingly sharp, and it's just as strong as blades made from Scarlet Crimson Iron Sand and Scarlet Crimson Ore. Plus, its fleshy make-up allows Kokushibō to alter the weapon to fit his needs and quickly regenerate it should it be destroyed.
Kokushibō was the first demon to use Breathing Styles — his signature version, Moon Breathing, is one of the most dangerous ones to ever exist. This technique gives him greater control of his sword, allowing him to perform many complex and reality-defying slashes that are near-impossible for the target to dodge. It also lets him create and fire a series of crescent-moon-shaped blades as he swings, creating a vortex of pain for anyone who gets too close to him.
Due to having Muzan Kibutsuji's blood, Kokushibō can use the Blood Demon Arts, which makes him terrifyingly powerful. Kokushibō's Blood Demon Art is named Crescent Moon Blades, and this ability boosts Kokushibō's Moon Breathing abilities, giving him greater control over his blades. Due to this, his moon-shaped projectiles are hard to dodge as they're constantly changing size and direction. While this ability is active, Kokushibō's sword swings are even more powerful, making him horrifically deadly in combat.
Kokushibō also has a Demon Slayer Mark due to training under Yoriichi Tsugikuni. When this mark is active, Kokushibō's abilities get a further boost. He can see and use the transparent world, allowing him to target specific muscles in his opponent and predict their movements via their blood flow, making him even more deadly. On top of all this, Kokushibō has lived for nearly 500 years and fought numerous Demon Slayers and foes during his lifetime. This means he has plenty of experience and knows how to handle himself in battle and counter many different fighting styles, allowing him to effectively strategize to beat any foe.
Who Could Beat Kokushibō?
Kokushibō stands as one of the most formidable entities within the realm of Demon Slayer. Progression through the ranks of the Twelve Kizuki hinges on defeating the current title holder. The fact that Kokushibō has maintained the top position for a prolonged period, despite the ambition-driven nature of fellow members, attests to his sheer might. This is exemplified by his effortless severing of Akaza's arm following a dispute about ranks. Consequently, it's logical to assume he surpasses Doma, Hantengu, Akaza, Gyokko, Gyutaro, and Daki, given they would have challenged him had they believed they could succeed.
Yet, it's likely that Muzan Kibutsuji, the progenitor of demons, eclipses Kokushibō's power. Chapter 180 substantiates this, as even with a mere fraction of his strength, Muzan effortlessly decimates a throng of Demon Slayers. During the final confrontation, Muzan remains a formidable threat despite being injected with body-deteriorating substances and power constraints. This underscores Muzan's supremacy, especially considering that a smaller contingent of Demon Slayers is enough to vanquish Kokushibō.
The significant question pertains to whether Kokushibō surpasses Tanjiro Kamado. This presents a nuanced inquiry, as Tanjiro's initial frailty gives way to swift growth, highlighted by mastering the Sun Breathing technique, a transformative enhancement. Although pivotal in Muzan's downfall, Tanjiro's accomplishment hinges on substantial assistance and a last-minute surge in power. In light of this, it's plausible that Kokushibō could prevail over Tanjiro individually prior to their final confrontation. This assumption assumes that Tanjiro lacks support from friends or other Demon Slayers, often his trump cards in dire situations.
Beyond Muzan Kibutsuji, another figure transcends Kokushibō, his sibling Yoriichi. Yoriichi stands as a preeminent swordsman and the originator of Breathing Styles, bestowing immense prowess upon their wielder. Yoriichi not only poses a substantial threat to Muzan but also inflicts substantial harm upon him, bringing him close to demise. During their ultimate battle, the elderly Yoriichi even wounds Kokushibō with a sword strike. This incites Kokushibō's fury, particularly as Yoriichi succumbs to old age before launching a decisive assault.