Demon Slayer: Infinity Castle review: "Roars past Mugen Train as Demon Slayer's best adventure yet"

In an industry filled with diminishing returns on comic book movies and a spotty track record of video game adaptations, anime appears to be Hollywood's next golden goose.

Leading the way is Demon Slayer: Infinity Castle, an epic (in all senses of the word, given its bumper 155-minute runtime) continuation of the hit shonen that promises to draw the series to a close.

Following on from the events of the divisive Hashira Training arc, Demon Slayer: Infinity Castle sees protagonist Tanjiro and his Hashira allies drawn into the titular Infinity Castle, a labyrinthine, ever-shifting structure that houses Big Bad Muzan Kibutsuji and his legion of Upper Moon demons.

From there, Infinity Castle wisely opts out of tracking the winding fates of the dozen or so characters trapped inside, instead splitting the core of the narrative into three main showdowns – including Tanjiro's headline fight against the Upper Three demon Akaza, who longtime fans will immediately recognize as the one who dealt the killing blow to Flame Hashira Rengoku in 2020's scorchingly brilliant Demon Slayer: Mugen Train.

But where the fights overflow with animation studio Ufotable's usual verve and vigor, Infinity Castle's narrative structure is altogether more conservative. The lack of a back-and-forth between battles, as one ends and another begins, means – early on – audiences won't be able to shake their biggest fear: that this is, cynically, six-to-seven anime episodes stapled together in a desperate attempt to chase box office dollars.

That layout, too, means Tanjiro largely doesn't enter the equation until well beyond the first hour, a baffling choice considering the poster boy is shunted to one side for a more minor – if no less entertaining – showdown between one of the Hashira and Upper Three, Doma.

Mercifully, Doma is one of Infinity Castle's surprise standouts. Slithering onto the scene with a serene sense of power, the Twelve Kizuki member is wonderfully unsettling and, thanks to a pair of razor-sharp fans as his weapon of choice, allows Ufotable to delve deep into its well of boundless creativity as sparks (literally) fly.

Infinity and beyond

While none of the demon-and-Hashira tête-à-têtes exceed the high watermark set by Akaza vs. Rengoku in Mugen Train on sheer spectacle alone, each bubbles over with a personal, emotionally charged undercurrent that turns a potentially taxing runtime into something altogether more palatable. It may be one of the longest anime movies ever made, but Ufotable's masterful deployment of backstory means Infinity Castle feels tighter than it has any right to be.

And that has long been Demon Slayer's secret sauce: it grew in popularity thanks to its hype moments and fighting spirit; it endures because of its heart. Anime picking apart a hero's journey or villain's motivations via backstory is nothing new, but never has it felt as potent – and series-defining – as it does here. Akaza is absolutely the greatest beneficiary of that approach, transforming a one-dimensional villain into a tragic figure in one fell swoop, proving that Ufotable can pull the heartstrings and punch guts with the best of them.

The air of finality, too, only bolsters Infinity Castle's quality. Far from being a sterile saga packed with plot armor, the peril-filled story revels in its suffocating sense of danger, with shocks aplenty and a poisonous brutality coursing through its veins at every turn.

Yet, there is a trio of elephants in the room. Demon Slayer: Infinity Castle is the first in a trilogy, a minor detail that has been conveniently left off the marketing here.

Infinity Castle, though, takes the road less traveled: the anime movie is less concerned with cliffhangers and, instead, fixated on continuation – as if it almost expects an audience to sit patiently for next week's episode to roll around.

Unfortunately for fans, it could be a painful, years-long wait until we step into the Infinity Castle once more, so there could be a small portion of the audience who finds its final act faintly unsatisfying and incomplete by its very nature – instead of triumphant.

But despite all the sticks you could beat Demon Slayer with – its structure, its runtime, its lack of a definitive ending – Infinity Castle emerges from the other side unscathed, all while showcasing the best-in-class action, a gripping story, and entertaining characters that have made it such a worldwide sensation.

Series veterans may rue the lack of certain supporting players (the hot-headed Inosuke is largely absent, while usual comic foil Zenitsu is all gritted teeth and gripped swords here) and the lack of levity may sting in a series renowned for its malleable tone and endless charm, but Infinity Castle achieves the impossible by roaring past Mugen Train as Demon Slayer's best adventure yet.

Demon Slayer: Infinity Castle releases in cinemas in the US and UK on September 12.

For more, see our picks for the best anime to watch right now. Need to catch up before Infinity Castle? We have a guide on how to watch Demon Slayer in order.