Demon Slayer Infinity Castle: Action and Emotion on the big screen

Written by Daniel MacKeith on 09 Sep 2025

Recently, I had the immense privilege of being able to attend the Demon Slayer Infinity Castle premier, at the Sony Pictures Entertainment UK office in London. Coming away from the experience, I feel that I must issue a warning to any and all people considering viewing this film: If you do go and see this film, you will be left with an incurable need to watch more. Unfortunately, despite this film being around 2 and a half hours long, it still did not feel like enough, this is because, through the magic of tireless effort and incredible skill, this film is a wild rollercoaster ride of intense fights, tear-jerking moments and a sprinting plot that had me savouring each moment, whilst still looking forward hungrily to the next. 

Just about anyone nowadays will have heard about the ‘decline of cinema’ and I’d be remiss to deny it entirely. But a title like this is still something that represents the best of what the medium can be: It is something that you can get excited for, an indulgent, bombastic bag of thrills, something that you can bring friends and family to or enjoy by yourself - either way it's hard not to get lost in the splendour of it all. Certainly, this is not an arthouse film, but it is exactly the kind of film that I’ve always loved going to the cinema to see: Some good old-fashioned fun, although it is certainly not without its fair share of heavy and dramatic moments.

In an age of streaming services, it is so easy to simply sit back and view at home when it's undeniably cheaper less hassle. However, I must annoyingly insist on the virtues of seeing this in theatres. I myself am not always a convert to these sorts of things, but seeing this film in the private theatre I was so lucky to be in, those barriers were torn down. Film is as much an auditory medium as it is visual, and my God, what audio. I could watch paint dry in that theatre: Every sound, every effect, every note of every song and every line from every character. I was surrounded by sound, flying around me at all angles, washing over me in waves. It was exhilarating.

They say that you think about what you see, but you feel what you hear, and I was certainly taken on an emotional journey. Ever since listening to ‘Gurenge’ when I first discovered the anime, Demon Slayer has had a soft spot in my heart just due to that theme alone. In this new film, there are many more such pieces of music, each coming in the right shape to suit the scene they were in. Without them, I would have been eating a meal without a drink, more than that, they are the lifeblood of this work. It is one of many things that I must take my hat off to and salute the work of Yuki Kajiura.

It has long been a talking point that the Demon Slayer franchise is ‘carried by the animation’. Certainly, in a genre that is known for action like Shonen, the quality of said animation is a factor in a show or film's success. I have to admit though, that in the case of this film, the quality of the work is impossible to ignore. This film is a sprint, each scene a moment to show off the kind of incredible amounts of action that can be crammed into the runtime. But it isn’t visuals alone that make a good movie, after all, the best tools can still be useless in the wrong hands. I would sum up this latest Demon Slayer film as essentially a series of fights, each its own theatrical story, with highs and lows, tragedy and hope, pain, loss, triumph and defeat, all unfolding against the background of one of the most impressive stages I may have ever seen.

Getting to that, it is pretty incredible that I’ve gone this far without mentioning the titular infinity castle that this film is so aptly named after, so here we go. It’s really cool. You really have to see it to really appreciate it. The castle is alive and the notion that our heroes are fighting the ground they walk on as much as the enemies in front of them is felt in just about every scene. The constant motion, the twists and turns, the unpredictability and the sheer scale of it all lights a fire behind an already thrillingly paced plot, infusing the film with this heightened feeling of urgency. We’ve come down to the endgame, every action counts now, and you just can’t miss a moment.

Warning: Major story spoilers ahead

Since starting Demon Slayer, one of the things that I always enjoyed was the recurring sense of hopelessness. Call me morbid, but I always appreciated those moments in which the obstacles ahead felt truly insurmountable. I relished in the crushing feeling that came from just how strong the demons could be, how when, faced by the kind of inhuman, almost incomprehensible power, our heroes had to face the possibility that defeat was almost inevitable and see how they would react with that knowledge in mind. When Rengoku faced down Akaza, when he threw everything he had into the fight, powered up as an anime protagonist appropriately should, had his shining moment of glory… and still lost, that to me was one of those moments that drove the stakes in deep, set a sense of just how hard the fight would be, how crushing a toll even victory could take.

Shinobu’s battle against Douma, one that viewers will be lucky enough to see, is one such example of this effect. Coming into the fight, we know just how strong Douma is, how high a wall he is to scale. We hope that Shinobu will have what it takes, we believe that she does, we will her to win. There is a white-knuckled intensity to her fight, she really is an insect stabbing at a larger foe, trying to bring down something so much larger than her, one sting at a time. So much flows into her fight, so much emotion, so much hope, so much will to win. It is delightfully unsatisfying to see his smug face still intact before the film is finished, and I can say that I will be waiting to see it wiped clean off rather eagerly. 

Douma, however, is rather the exception to the rule. So much of the heart in this series lies in how it humanises its villains, how, even though we may not forgive them, there is much effort put into making us understand them, to perhaps wonder if we could be them, if we would have done any differently given the circumstances. This film has two beating hearts to it, and both are suitably heart-wrenching, although, for me, one hit just a little bit harder. Starring in his very own solo fight, Zenitsu’s outing hits all the right beats. The personal feel of this fight hits hard, the emotions run high, and I can safely say that this has to be my favourite outing from the character. The pain that can be felt through the interactions between him and Kaigaku is both crushing and poignant. There is a true sense of tragedy in Kaigaku’s inability to properly see what Jigoro has become, and yet it is hard to feel truly sorry for the unrepentant former student, only a deep sense of pity. If this was an appetiser, the main course was still to come. 

I had heard a lot about Akaza’s backstory, that it was the saddest, the most tragic, the most tear-jerking. It certainly did not disappoint. Hints of it are sprinkled throughout his desperate fight with Tanjiro and Giyu, small slivers of sadness slipped in between moments of intense all-out action. Little by little, more pieces of the puzzle are put together, until all at once the floodgates are opened. I’m no stranger to the sad backstory, as someone who has followed the series for a long time now, I know the drill. But I will say, something does hit quite hard about seeing it all unfold. Akaza’s journey is such a hard one, and there was so much that he lost, so much that could have been. The feeling of a man that is truly empty, who had nothing and lost everything, driven on by the last faint bits of hope that he still had left to cling onto. I’m hardly ashamed to admit that I teared up during his story.

It perhaps makes it hit all the harder that, with this film finished I am so excited to see what’s next. If Akaza was the one who could be redeemed, I am excited to see the irredeemable. Muzan still lies in wait, and Douma is still not dead. Kokushibo is yet to make his appearance proper, as are the rest of the true heavy hitters of the Hashira. This film was a feast, and there is still so much more to come. I hope they take their time with it, maintaining the high standards set by this film and most of all I hope that you go see this one in cinemas as soon as you can. I promise it won’t disappoint.