Demon Slayer: Infinity Castle movie review - A gripping and gorgeous anime spectacle

The anime's film adaptations tend to slice through records like protagonist Tanjioro and co slice through monsters. Mugen Train, for example, became the highest worldwide grossing film of 2020, and Infinity Castle’s earlier release in Japan quickly broke every weekend box office record in the country.

Now that we’ve seen the latter for ourselves, we’ve been reminded why. While this is absolutely not a film for newcomers or those who are multiple seasons behind (unless they're into spoilers), fans who’ve been keeping up with the worldwide phenomenon that is Demon Slayer will be more than happy with the finale’s first slice.

Infinity Castle starts exactly where episode 8 of the anime’s fourth season left off, at the conclusion of the Hashira Training arc. While there's a brief snippet of the ending to remind you of where it left off, rewatching the finale — or catching up in general, if you haven’t already — is best if you want the most cohesive watching experience.

Although Kagaya Ubuyashiki and Lady Tamayao got the drop on Muzan Kibutsuji, it came at the cost of the former sacrificing himself and a few loved ones via a huge mansion explosion. In the aftermath, the Demon King has hidden himself away in his base — the titular Infinity Castle — to recuperate.

As all the Demon Slayer Corps are trapped and scattered inside the vast space, Tanjiro, Zenitsu, Inosuke, and the multiple Hashira must find Muzan to defeat him. But, of course, it won't be easy as they must face the remaining ultra-powerful Upper Rank demon minions they run into on the way.

On paper, the decision to dedicate the entire remainder of Demon Slayer’s Infinity Castle arc into a film trilogy from the get-go, rather than one at a time, is a curious one — since it could make any of the entries potentially bloated depending on their content.

In execution, this approach does make the pacing more engrossing.

Foremost, though, turning the arc into a feature film appears to have unlocked a much higher budget for the animation, allowing studio Ufotable to make Demon Slayer look more captivating than ever.

Although it didn’t seem possible already, Ufotable has marked Infinity Castle as the point where they’ve polished their craft even higher, wowing us as much as back when they broke the internet with episode 19 of season 1 all those years ago.

Weekly episodes in the anime definitely have cinematic flair, but with the latest feature-length budget, the results are staggering.

The blend of the Infinity Castle’s 3D environments and 2D character work was seamless, more so when going from the castle's constantly shifting halls to the constantly dazzling elemental sword attacks.

The multiple elemental Breathing Styles of the many swordsmen we’ve come to love over the years have always impressed visually, but this latest movie seems to make scenes leap off the screen with a higher fidelity all around, upping the weight and impact of every blow as a result.

That elevation can be felt in the audio too, with an ear-pleasing soundscape provided by returning Demon Slayer composers Kajiura and Go Shiina, who gently reaffirm why they're some of the best composers in anime right now.

This is paired with impeccable voice-acting across both the sub and dub and a delightful score with new vocal centrepieces, Taiyō ga Noboranai Sekai by Aimer and Zankoku no Yoru ni Kagayake by LiSA respectively. The result encapsulates Demon Slayer’s tragic undertones and the raw emotional fire of the series's final battles.

Even the finely placed comedic moments, portrayed through the hilarious dumbfounded facial expressions that usually shine best in the manga, feel more pronounced. They're also placed in the right moments, and don't clash tonally with the most important fights

One such brawl is with Insect Hashira, Shinobu Kocho, whose own arc and motivations are finally revealed. As with the manga, her fight is a particular standout, worthy of a cinematic screening with fast-paced flourishes, larger-than-life effects, and quiet rage bubbling over her once-peaceful demeanour.

That further boost in animation quality also heightens the increasingly terrifying nature of the upper rank demons like Doma, Upper Rank #2 , who accentuates a carefree elegance and beauty whilst being one of the most nefariously evil demons of them all.

Although Zenitsu is usually a source of added levity in the Demon Slayer franchise, this film delivers his most defining moment yet — a breathtaking sequence where his fear finally gives way to conviction after discovering a deeply personal connection to one of the Castle’s foes.

Although this is another example of where you definitely need a refresher of the Hashira Training arc to understand all that’s going on, his transformation from comic relief to true warrior is both satisfying and thrilling to watch unfold.

It’s around the halfway mark when the action really gets turned up to 11, though. That's when Akaza finally rejoins the conflict directly. Alongside being a narratively satisfying follow-up to Tanjiro’s arc, set in motion with Rengoku’s death, it provides a flurry of well-animated fight choreography — everything’s kept at an incredible jaw-dropping pace, but still drawn well enough so viewers can tell what’s going on.

After all, the best part about these huge boss fights in all of Demon Slayer is that one wrong move during a big attack could cost a key character’s limbs or even their lives. Watching Infinity Castle, it’s more suspenseful than ever.

Fight choreography is depicted as an increasingly artistic yet monstrous dance between blades, fists, and other demonic weapons, and gets sharper as the film goes on.

With most of Demon Slayer: Infinity Castle focusing on Akaza, however, other stories explored in this part of the trilogy do end up taking a back seat. That’s including one in particular being left on a cliffhanger, which can be frustrating for anime-only fans who don’t want to read ahead with the manga, considering other elements that were lent screen time instead.

It could be argued that this is to remain faithful to the source material, something the animation is also serious about. Besides, adding a resolution to that storyline might've felt too long considering how much time is spent on the fight scenes.

Still, the third act can feel about 10-15 minutes too long coming after the already sizeable Akaza fight. If you’ve only watched the anime up until now, and if you don't know what happens afterwards, we wouldn't blame you for coming away frustrated.

As a reviewer who knows what’s coming next after reading the manga, though, Infinity Castle does end at the right place, and sets up the next step for Tanjiro’s ‘revenge for Rengoku’ arc, started back in Mugen train.

And, of course, the even bigger battle to come.

Albeit slightly disproportioned in the way it spins the first batch of the many plates that make up the manga’s final arc, part 1 of the Demon Slayer Kimetsu no Yaiba: Infinity Castle is a gorgeously crafted anime spectacle that does its source material justice.

Newcomers should stay away, but because Ufotable understands its core audience well enough, this has been almost perfectly catered to Demon Slayer’s many fans across the world, working as a high-octane, action-fuelled upping of the stakes. Even when considering the manga, it’s both the most gorgeous and the most gripping Demon Slayer has been yet, and makes us want to jump into part 2 right away.

Demon Slayer: Infinity Castle part 1 is in UK cinemas from 12th September.

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