With the Demon Slayer Infinity Castle movie already in circulation for the global releases, one of the most highly anticipated battles from the movies is the one between the new Upper Rank Six demon Kaigaku and the Slayer Zenitsu. The battle not only holds a significant value in the lore, but also can make or break the series.As the series has built up the fight between the two former acquaintances massively, it became one of the biggest moments in Zenitsu's character arc and holds a significant amount of hype for the movie.Disclaimer: This article contains massive spoilers from the Demon Slayer Infinity Castle movie.Zenitsu vs Kaigaku is one of the biggest highlights of the Demon Slayer Infinity Castle movieIn the Demon Slayer Infinity Castle movie, one of the major fights the series focuses on is the fight between Zenitsu and the new Upper Moon Six demon Kaigaku. The hype for the battle has been put into motion by the series from the very moment Zenitsu received a letter in the Hashira Training arc. His entire aura shifted to someone more determined and serious.As the Demon Slayer Infinity Castle movie revealed, the letter carried news regarding both Zenitsu and Kaigaku's former master and the former Thunder Hashira, Jigoro Kuwajima. As the letter revealed, after Jigoro learned that Kaigaku had betrayed the Slayers and become a demon, it was too much for him, and he committed Seppuku.The letter also revealed that he was alone in his final time and died painfully. The letter triggered something within Zenitsu that changed his entire personality. Jigoro, besides being Zenitsu's master, was also his grandfather, and a sense of vengeance for his death began flowing through Zenitsu as he entered the Infinity Castle.Thunder Breathing 7th form as seen in the manga (Image via Shueisha)Kaigaku and Zenitsu's narrative while they were training under Jigoro was also a reason the animosity between the two was triggered. While Kaigaku always received praise from others for mastering all the Breathing Forms in Thunder Breathing, Zenitsu was mocked for only being able to learn one, the first form.While Zenitsu also respected Kaigaku a lot, the latter had no respect or regard for the former. The movie featured a back and forth between the two, and when Kaigaku thought he had the upper hand, Zenitsu pulled out a Seventh Form that he invented- Honoikazuchi no Kami, beheading Kaigaku. As the two of them were falling, Yushiro appeared and grabbed an unconscious Zenitsu, saving him.The battle is one of the most highly anticipated battles in the first movie and has been hyped up as such by the franchise. While Ufotable, the animation studio, has earned a reputation for its quality production, what they do with the fight will make or break the franchise.Final thoughtsshi @gojoismLINKit’s so sad that even after zenitsu defeated kaigaku he still blamed himself that he became a demon. he didn’t have a chance to get over that and just headed straight to the next battleThe Demon Slayer Infinity Castle movie is a very important part of the series' lore, as what happens to the focused characters from the first movie heavily impacts the rest of the story narrative. Furthermore, Zenitsu's triumph over Kaigaku is something that manga fans and those who have already seen the movie know is a big deal for the series, hence the need for it to be well portrayed.Also read:Demon Slayer Infinity Castle movie overtakes Frozen and Your Name to set yet another box office recordFirst Demon Slayer Infinity Castle movie English dub casts Channing Tatum and Rebecca WangThe first Demon Slayer Infinity Castle movie continues to set new box office records with its international release