The final battle against the demon Muzan Kibutsuji ignites in Demon Slayer: Infinity Castle, the first film in a trilogy that will conclude the monumental series. Marking the start of the crucial Infinity Castle arc, the film opens at what should have been the Demon Slayer Corps' moment of victory, only for the ground to disappear beneath them, transporting everyone to a surreal, ever-changing place. Scattered and without a clear plan other than to find Muzan before it’s too late, the Demon Slayers must frantically face off against every living demon, particularly some of the terrifying Upper Rank adversaries.
The stakes are higher than ever before, and the tension reaches indescribable levels simply because of the fact we're thrown into the enemy's lair. A lair that is filled with his many dangerous minions, which makes us constantly think about how no one is safe.
We know from previous seasons that Demon Slayer is not shy about killing its characters in order to move the story, and so, for those who haven’t read the manga, this movie—or the subsequent ones—will feel like a gamble since nothing is set in stone.
Did you hear that? Those were my agonizing screams when I read the manga.
A Spectacle for the Senses
Once again animated by the legendary studio Ufotable, the film is universally praised as a visual marvel, and trust me, that isn't an exaggeration. Under the direction of Haruo Sotozaki, the animation flawlessly combines detailed 2D hand-drawn digital animation with integrated CGI elements, resulting in a visually striking experience that surpasses even their previous benchmark work on Mugen Train and the Fate series. Every single frame is phenomenal, crafted with a level of uncompromising quality few other anime can boast—a hill I'll gladly die on.
Beyond the visuals, the sound design is equally masterful. The visceral quality of the audio—from the distinct roar of each Breathing Technique to the metallic clash of Nichirin swords—makes every blow feel grounded and painful, amplifying the intensity of the action.
The film focuses on three major, bloody showdowns that deliver inventive and gorgeous combat sequences, each distinctly unique. We have two duels that act as emotional climaxes, basically completing the background stories for a couple of our main characters, and one confrontation that, ironically, serves to erase the history of its combatants.
The Infinity Castle Showdowns: A Deep Dive into the Battles
The Shinobu Battle
I remember reading this part like it was yesterday, with Shinobu being one of my favorite characters. Ufotable absolutely did justice to her battle, and I think they even augmented the scene's intensity through sound design. We could clearly hear the sound of her gasping for breath and her strained efforts to continue. Don't get me wrong, I feel like that sound gave me emotional damage, but it made the entire experience more immersive than I could ever have hoped.
Douma has to be one of the scariest demons ever because of his horrifying playfulness and lack of genuine emotion. It’s truly unsettling that since a young age, this kid basically had no empathy for others. He felt pity for humans the way you might feel bad about a child losing their favorite toy—a profound sense of disconnect. The fact that Shinobu almost made it speaks volumes about her power, not only her speed and precise technique but her brilliant, strategic mind. She knew exactly what she had to do from the start.
The Zenitsu Battle
Look, I've never been a huge fan of Zenitsu; I don't hate him, but I don't particularly like him. However, when I noticed his distinct change in demeanor starting from the Swordsmith Village Arc, I was immediately curious. Zenitsu is never shy about expressing his emotions fully, like it or not, and seeing him so withdrawn and even angsty intrigued me.
Well, it turns out he had a very good reason—one that wouldn't just define the legacy of Thunder Breathing but would finally settle his complicated family situation, or lack thereof. This confrontation was arguably the shortest of the entire movie, but I can't blame anyone other than the nature of the breathing style itself. I've always felt that Thunder Breathing fights are meant to be short, sharp, and lethal, and that's precisely what we witnessed: a brief, lightning-fast affair where the outcome was decided in a single, devastating moment. The debut of his newest form was pure spectacle.
The Tanjiro & Giyu Battle
This was the longest and arguably the best-choreographed battle in the movie. Akaza stole the show for me. His fighting style, marked by his Destructive Kill techniques and his terrifying Compass Needle ability, was not only visually cool but was clearly tied to his tragic backstory. This makes him such a well-rounded and compelling enemy, not just a monster to be defeated.
The effects, once again, were fantastic. I particularly loved how the background shifted and warped to emphasize the raw power and destructive magnitude of the battle, contrasting the Demon Slayers' elegant Water and Sun Breathing forms with Akaza's explosive strikes. The dynamic between Tanjiro's desperation and Giyu's focused resolve made for an incredible partnership against the relentless Upper Rank Three.
Music and its Impact
The whole presentation is also bolstered by fantastic music, with the score and new songs from artists like LiSA ("Shine in the Cruel Night") and Aimer ("A World Where the Sun Never Rises") perfectly matching the visuals and emotionally enhancing the dramatic moments. Personally, I feel like these two tracks are going to become unforgettable.
The Unsung Heroes: Background Characters and the Corps
I also feel the need to specifically mention the vital participation of the background characters. While their roles were established in the manga, I absolutely loved how much more screen time and agency they seem to have been given in this installment. While many viewers focus only on the Hashira, I think it’s genuinely refreshing to see these lower-ranking Slayers in action, playing a substantial part in this lethal game and showcasing the fruits of their rigorous training.
Remember that all of them went through intense physical and mental conditioning, just like the main Demon Slayer Corps members. Seeing that shared training come to fruition in this movie is a great payoff; it emphasizes that every single life matters in this final operation. No job is too small for anyone here, everyone's contribution matters.
This sense of universal duty extends beyond the fighters. Every single member of the organization, from the dedicated, retired Slayers who are dutifully protecting the leader's children to the tireless Kasugai Crows delivering vital messages, has a crucial role to fulfill. This interconnectedness not only makes the story great but gives you a clear vision of the overwhelming odds they face. It underscores how absolutely detrimental it is that Muzan must be destroyed, as his presence threatens not just a small organization, but all of humanity.
Finally, it's both heartbreaking and admirable seeing the deceased leader's children—the Ubuyashiki successors—not only continuing his legacy but fighting against their natural instinct to mourn their parents and sisters. They demonstrate an extraordinary discipline, as they haven't allowed themselves a moment to grieve in peace while the battle for humanity is still raging.
Story and Pacing: A Personal Defense
At this point, Infinity Castle is a late-stage story arc that unequivocally assumes the viewer is already familiar with the series, its characters, and their relationships. While some reviewers noted that the animation and action might still be enjoyable for newcomers, it's definitively a film made for invested fans who have watched the previous seasons and are seeking the emotional payoffs for characters like Zenitsu, Shinobu, and the brother-like bond between Tanjiro and Giyu.
I know some people are criticizing the film's structure and pace due to the lengthy character backstories, but personally, I had no major issues with it. I think Demon Slayer, from the very beginning, solidified itself as a battle shōnen deeply intertwined with character tragedy, and within that structure, flashbacks are bound to happen. Expecting the adaptation to deviate from this core narrative device at this stage is unrealistic, as that would essentially result in a completely different anime.
I’m just saying it could have been far worse, like the Swordsmith Village Arc, which at times felt exhausting due to the many interruptions in the middle of battles that didn't quite let our badass Mist and Love Hashira shine.
We also need to consider that, in terms of storytelling, flashbacks always have an intention. For most of the demons, it's just to give us a fleeting glimpse into the desperate decisions that led them to where they are today. Nevertheless, there are a couple of crucial cases where we get longer, deeply humanizing flashbacks meant to make us empathize with, or even like, these characters—and Akaza’s backstory remains one of the best examples.
His backstory was absolutely needed because without it, you wouldn't be able to truly empathize with him in the long run. I understand that the emotional weight felt intense, but that was the intention: to show that not everything in this world is black and white. It highlights that the influence of demon powers goes beyond a simple change; it amplifies and warps a person's existing emotions and regrets to the point that they become unrecognizable, no longer the same being they once were. This isn't to say all demons are secretly good, but that their power acts as a dark, controlling force. In fact, part of Akaza’s backstory felt slightly rushed, so I think, in terms of "summarizing" his tragic life, the production team did an excellent job with the time constraints they faced.
Would I have preferred a longer version of this? Absolutely. I think Akaza’s arc is one of the best, if not the best, in this story.
A Series in the Making
Given that the studio re-released Mugen Train as a series with expanded content, there's speculation that Infinity Castle will follow suit, offering a more "digestible" pace for those who had issues with the long runtime.
Final Verdict and Looking Ahead
All in all, I loved the story, I still adore the characters, and found the film to be a genuinely satisfying and visually engaging setup for the rest of the trilogy. The emotional depth and unparalleled spectacle make it a powerful cinematic experience.
I'm incredibly excited for the next movie, and when I tell you you're not prepared, believe me! I'm sad to report that things only get more intense and significantly darker from here, setting the stage for what will be a conclusion many don't expect.
Have you had a chance to see Demon Slayer: Kimetsu No Yaiba Infinity Castle? If so, what did you think of the animation and the pacing?
