This post contains SPOILERS for theDemon Slayeranime and manga.
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The first movie of theDemon Slayer: Infinity Castlearc is inching close to its theatrical release, and fans are getting eager to see the final battle betweenDemon Slayersand Upper Moons unfold.Infinity Castle, which will be covered in three movies, will feature several much-awaited battles. This includes the fight between Tanjiro and Akaza and, of course, Shinobu and Doma; that’s only the beginning, though, as humanity’s warriors will also go against Muzan.
That being said,Infinity Castlewon’t only be driven through action, as the story arc will also dive deeper into the story. The three-part movie series will shed light on the backstories of some powerful Upper Moons, including Akaza. However, fans are most eager to learn about the origin story of the strongest Upper Moon, Kokushibo.
Kokushibo’s Significance In The Story OfDemon Slayer
He Is The Strongest Living Demon After Muzan
Kokushibo may not have appeared intheDemon Slayeranime much, but heholds great significance in the story. The warriors of humanity have been fighting the demon race for centuries, and well, Kokushibo is thestrongest demon to ever live, after Muzan, of course. He is the strongest Upper Moon, which meansonly the strongestDemon Slayeralive, Gyomei Himejima, can defeat this monster. So far, the anime series has showcased only a couple of fights with the Upper Moons; however, these fights were more than enough to give us a taste of the Upper Moons' strength. In a way,these battles with the Upper Moons have set up the ultimate fight against Kukushibo, because he’s the one sitting on top.
Kukushibo, or the Upper Rank One, became a demon after being turned by theDemon King Muzanhimself. As a human, Kokushibo was a skilled swordsman, and he had already developed theDemon Slayermark. So, you could say that he instantly became a fearsome demon after getting turned. Additionally,Kokushibo developed Moon Breathing, which, although derived from Sun Breathing like all other breathing styles, was still anincredibly powerful breathing technique. Of course, Muzan was strong, but it was Kokushibo who killed the leader of the Demon Slayer Corps at the time.
That’s not it, though; sinceMuzan got terrified of Sun Breathing after encountering Yoriichi,it was Kokushibo who helped Muzan kill everyDemon Slayerwho was using the breathing style. So, it’s safe to say that it was Kokushibo who helped Muzan exert his dominance over humans and demon slayers during the Sengoku era.
Kokushibo’s Position As Upper Moon One Remains Unchallenged
The Upper Moon Rankings inDemon Slayeraren’t permanent, as a demon can take a higher ranking after growing in strength. For instance, Doma was an Upper Rank Six a century ago, but after becoming more powerful, heascended to the position of Upper Rank Two. However, there was absolutely no one who could challenge the might of Kokushibo. He became a demon approximately four centuries ago, and all this time, he held the title Upper Moon One. ForgetDemon Slayers;even the rest of the Upper Moons fear the strength of Kokushibo.
Upper Moon One’s Connection With The StrongestDemon SlayerTo Ever Live
Kokushibo Was The Elder Brother Of Yoriichi
Ever since Tanjiro joined theDemon SlayerCorps, he hasheard Yoriichi’s name multiple times. Yoriichi was the strongestDemon Slayerto ever live; in fact, he’s theonly human that Muzan feared the most.Well, Yoriichi’s past is closely tied to Kokushibo, as they are brothers. Kokushibo was the older brother of Yoriichi, and, in fact, it was Kokushibo who sort of inspired Yoriichi to pick up a sword for the first time.
Yoriichi had no desire to become a swordsman; it was always Kokushibo’s dream. Yoriichi liked seeing his older brother training with a sword, so he unlocked his true potential after getting inspired by Kokushibo. However, little did Kokushibo know that his younger brother possessed some natural talents and would eventually become an even better swordsman.Yoriichi started developing Sun Breathingbefore he was ten, so Kokushibo’s jealousy continued to grow.
I will stop your bleeding. Humans are so fragile. However… if you bleed to death… or if his lordship doesn’t approve of you… and you die… then death was always your fate. In that case… you were no greater a man than that. Don’t you… agree? - Kokushibo
However, the boys separated after their mother’s death, and while Kokushibo became a family man, Yoriicho became aDemon Slayer.They may have walked on different paths, but their fates were aligned. So, the brothers unite after some years, and instead of feeling joy at meeting his younger brother, Kokushibo grows more jealous because of the fact that Yoriichi has become the strongestDemon Slayer. That’s whenKokushibo decided to leave his family behind and train with his brother as a fellowDemon Slayer. But guess what? Despite all the hard work, Kokushibo couldn’t surpass Yoriichi’s natural talents. Even developing Moon Breathing couldn’t change anything for Kokushibo.
The Fear Of Death Compelled Kokushibo To Become A Demon
Like Yoriichi, Kokushibo alsodeveloped aDemon SlayerMark, which some might think would have been a good thing to boost Kokushibo’s confidence. But that’s not how Kokushibo perceived this; in fact, it was the very thing that made him accept Muzan’s offer to become a demon. Apparently,everyone who developed aDemon Slayermark would die at the age of twenty-five— that’s the curse of the mark. And well, Kokushibo just couldn’t accept this fate, as he wanted to grow even stronger. So, he decided to become a demon after all.
Kokushibo didn’t become aDemon Slayerbecause of his love for humanity; he had no interest in saving humans. Instead, he joined the demon slayer corps so he could surpass Yoriichi. From Kokushibo’s perspective, becoming a demon would not only save him from the curse but also help him become stronger than his younger brother. But years later, whenKokushibo encountered Yoriichi, he learned that his younger brother was still stronger than he was as a demon. Not only that, butYoriichi also survived past the age of twenty-five despite developing the demon slayer mark. You could say that Kokushibo became a monster for nothing, and he realizes the same thing during his final moments in theInfinity Castlearc.
Kokushibo Will Possibly Get The Spotlight In The SecondInfinity CastleMovie
It Will Be A Battle Like No Other
The firstDemon Slayer Infinity Castlemovie will possiblyfeature the fights against Akaza, Doma, and Kaigaku.So, we can expect the Hashiras gathering against Kokushibo in the second movie before we get to Muzan in the third and final film. Kokushibo’s fight will surely beone of the best fights we see in theDemon Slayeranime.
It will take more thanStone Hashira’s efforts to take down this beast.Apart from the battle sequence, the origin story of the Upper Moon One will be one of the most impressive parts of the movie. He spent all these years as a demon and let go of his real identity, but in the end, he will realize that it was for nothing. And fans will surely shed a tear the moment Kokushibo realizes this in the movie.
The firstDemon Slayer: Infinity Castlemovie isscheduled to release in the United States on September 12.
Demon Slayer
Based on Koyoharu Gotouge’s shonen manga, Demon Slayer: Kimetsu no Yaiba is an action anime set in Japan during the early 20th century. Seeking revenge for the murder of his family while also looking to save his sister, Tanjiro joins the Demon Slayer Corps as they try to eradicate Demons led by Muzan.
