As io9 has thoroughly glazed in detail, 2025 was a definitive year for anime films, thanks in part to the meteoric box-office success of Demon Slayer: Infinity Castle. As the film prepares for award season, its directors shared some behind-the-scenes tidbits about how studio Ufotable pushed past their limits (and the laws of physics) to bring the megapopular anime’s bombastic fights to life.
Speaking with Entertainment Weekly, Infinity Castle director Haruo Sotozaki, director of photography Yuichi Terao, and Ufotable president Hikaru Kondo reminisced about how the studio’s commitment to making the best anime possible contributed to the film being at the table this award season.
In the movie, hero Tanjiro Kamado and the rest of the Demon Slayer Corps dive straight into enemy territory, battling an onslaught of powerful enemies and overpowered bosses in the ever-shifting maze that is the Infinity Castle. While this isn’t Demon Slayer‘s first rodeo in cinemas, Infinity Castle marks the beginning of the end of the banner series as the first of a film trilogy. Having the first leg of that trilogy play in IMAX theaters inspired Ufotable to elevate the streamer anime into a cinematic experience. The studio wanted to ensure that every corner of the screen was popping with detail, which required collaboration in its compositing of 2D characters moving through 3D environments in its fluid action sequences.
“If you look at a lot of the keyframes, the key animation, the sakuga in this film, we worked really closely with our 3D department to make sure everyone’s in full lockstep because we didn’t want any weird bizarre effects where perhaps these 2D characters are sliding around on the 3D surroundings and environments,” Sotozaki told EW. “So it was very important that the 2D keyframe animators were talking to our 3D team to make sure the compositions were perfect.”
On that front, Sotozaki told EW that the most complicated aspect of bringing Infinity Castle to life was ensuring that its 3D environments and animations were all in sync. To prevent oopsies during production, he said Ufotable would often test keyframes in their respective 3D environments before finishing key animations. While hero Tanjiro’s secret to success is his impeccable breathing techniques, Terao explained that Ufotable’s animators would hype themselves up with music so that, once pencil hit paper, Infinity Castle‘s many set pieces and sequencing momentum would pour straight into its animation.
“Whenever you see Tanjiro saying, ‘Don’t give up,’ the animators are probably doing something similar with their headphones on,” Terao said. “I’m on the digital 3D side of things, but I know this is especially true for the keyframe animation team, the 2D animators. Whenever they want the characters to perform certain actions, they would sometimes get up from their desk and actually act out some of these action sequences. So if you catch this out of the corner of your eye, sometimes you might wonder, ‘Are they just cheering themselves on or dancing or are they trying to act something out to see what the animation would look like?’ It’s kind of an interesting sight to see.”
By far the biggest hurdle for the team was Infinity Castle‘s final fight between Tanjiro and Akaza, which Sotozaki said was led by four people at Ufotable. Key among them was key animator Masayuki Kunihiro, who Sotozaki explained handled 80 percent of Akaza and Tomioka’s physics-breaking fight.
“It’s quite tricky action, but very fast action. I mean this in a good way, but it’s unrealistic in the sense of how fast the characters can move and what they look like on screen. It’s very convincing to the viewer, but it defies physics,” Terao said. “If you’ve seen the film, you will understand what we’re talking about. The first time we’re trying different types of animation where parts of the Infinity Castle either shatter, breaks, or collapses, there’s a lot of destruction. And take, for example, when Akaza smashes the ground. It shatters and you have this smoke, but all of this needs to be simulated in CG in these different physics engines.”
“The irony is, when you look at Kunihiro’s animation, you’ll flip one frame of paper and the characters will move like 100 meters, which in real-world physics is impossible. So a lot of the simulation that we tried to run on how things shatter, making that hybrid between the 2D animation and the 3D simulation was quite challenging,” Sotozaki said, getting more into the nitty-gritty of how the anime sausage was made.
He continued: “It was fun, but challenging because there really are no settings that allow such fast physics to happen by how the physics engines are computing the different simulations. So I think he has a very unique pipeline, too. Oftentimes we’ll have 2D action animators match the action to the 3D environments or the shot composition, but Kunihiro is the exception to this and we allow him to make the action keyframes first and the 3D team actually has to match the 3D environments to whatever he gives.”
The trio unfortunately said they couldn’t provide an update on when fans can expect the second installment of Demon Slayer‘s film trilogy finale or what the future of Demon Slayer might look like once the trilogy concludes. This response, in concert with the Crunchyroll president’s FOMO-fueled “better watch it in theaters while you can” response to anime fans asking when they can expect the film to arrive on the streamer, is pretty disheartening.
However, Sotozaki assured fans that Ufotable will continue striving to deliver a consistent level of animation quality for the final legs of Demon Slayer‘s theatrical series finale.
“At the studio, we always try to meet and exceed audience expectations and create an experience that everyone can enjoy and the entire team and staff share this sentiment, so do with that information what you will,” Sotozaki said.
In io9’s review of Infinity Castle, we too lauded the film for its flashy animation and action sequencing, writing, “Ufotable’s animation is as dazzling as ever, with slick camera movement that has its characters ping-ponging through 3D CG backgrounds, complemented by compositing finesse that gives the film a cinematic grandeur exceeding that of past films like Mugen Train. Its action choreography is a rollercoaster for the eyes—fluid, explosive, and occasionally slowed down, as if to let sparks fly off katana blades like fireworks behind your eyes. And its final battle kicks things into third gear.”
Clearly, Ufotable’s reputation as the anime studio to watch has borne fruit this year, because Infinity Castle got a Golden Globe nomination for Best Animated Feature Film. Chainsaw Man – The Movie: Reze Arc, despite being equally excellent, didn’t make the cut, so all Demon Slayer has to do is beat out its fellow nominees (including heavy-hitters KPop Demon Hunters and Zootopia 2.) Like Issa Rae at the Emmys, we’re rooting for everyone anime.
Want more io9 news? Check out when to expect the latest Marvel, Star Wars, and Star Trek releases, what’s next for the DC Universe on film and TV, and everything you need to know about the future of Doctor Who.
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![This former notorious red-light district is now one of the world’s top AI hubs | TechCrunch
What every U.K. AI startup wants to know these days is, how can I get office space in King’s Cross?
The area is so hot that a VC firm allegedly recently won a deal by promising a founder office space in the neighborhood. “We stop at nothing to win deals [for] and to support” founders, “including helping them source office space when needed,” the firm told me when asked about the rumor, declining to confirm or deny any details.
The neighborhood’s popularity began back in 2016 when DeepMind — then newly acquired by Google — moved in. Soon after, a flood of AI startups followed, wanting to be around the Google DeepMind magic. Today, they hope to take advantage of the cluster of AI talent there.
This has transformed King’s Cross into one of the world’s top AI hubs, rivaled only by San Francisco and Beijing. Around London, it’s known by the sobriquet “Knowledge Quarter,” as it’s home to names like OpenAI, Meta, Isomorphic Labs, Cusp AI, Wayne, Recursive, and, a little farther down the road, Synthesia and Anthropic. The European Technology Network (ETN) just moved into a glossy new office nearby, while University College London sits around the corner.
Mixed in with the new developments are trendy food spots like Hoppers and BAO. Hop a train from King’s Cross, and founders can be in Cambridge in 45 minutes to source talent or can be in Paris in two hours to strike a deal.
Who would have guessed that a little more than 20 years ago, this was one of the seediest areas in London?
“In the ’80s, crack and heroin made the area a major narcotics market,” Hussein Kanji, an investor at Hoxton Ventures, said, recalling syringes in tree trunks and gangs patrolling the streets. “In 1982, the local church was occupied by the English Collective of Prostitutes for 12 straight days.” Then, in the early 2000s, a real estate developer had a dream and, well, “now it is the AI hotbed of the United Kingdom,” Kanji said. “What a change.” Around 18 months ago, his portfolio company BioCorteX moved from the neighborhood Holborn to the Jellicoe building in King’s Cross, hoping to be near the action. “Lots going on in London right now,” Nik Sharma, co-founder of BioCorteX, told me. “Lots of hyperscalers moving in.” That includes, reportedly, Jeff Bezos’ AI company Prometheus, which is also said to be in talks to move into the Jellicoe.
There are around 3,600 AI startups in London, which, together, have raised around .1 billion out of the .8 billion raised in the city since late July, according to Dealroom. Since the start of June, AI-related startups have leased more than 1 million square feet of office space in London, according to the real estate firm Knight Frank. With that, prime rents in King’s Cross have risen 18% over the past three years, Chris Dunn, a commercial insight associate at the firm, told me. That percentage represents only the largest leases encompassing at least 10,000 square feet, like the ones OpenAI and Prometheus are signing. The shorter deals go for even more, he said, and now the vacancy rate for conventional office space is just 0.9%. “Demand has outstripped supply,” he continued.
Today, one of the big topics of the area is sovereignty. It was a wake-up call for many when Anthropic shut off access to Mythos and Fable this summer, leaving some in the ecosystem to conclude: “We’d better look after ourselves,” Saul Klein, co-founder of the VC firm Phoenix Court, told me.
Phoenix Court is located in the King’s Cross area and has three portfolio companies in the vicinity, including Olix (which just announced a .3 billion valuation), Early Health and CoMind. Robin Klein, co-founder of the firm, said the shutdown of Fable and Mythos access was a “small but sharp reminder that Europe can’t simply rent its AI capabilities and capacity; it needs to build and hold some of its own.” King’s Cross, he said, is where much of this building is actually happening.
“The bigger question,” he continued, “is whether the U.K. builds the infrastructure, compute, energy, capital, to make this self-reliance durable, rather than just hosting outposts of U.S. labs.”
Image Credits:Phoenix Court
Top founders want to stay
Simon Kohl, founder of Latent Labs, has offices in King’s Cross and San Francisco. The London office, at the moment, is growing faster, and he’s more bullish than ever on the ecosystem, he said. “The mood right now feels less like London trying to catch up and more like London becoming one of the default places to start a serious AI company,” he said. Look around and you are likely to see Wayve testing its autonomous cars. Founded in 2017 by co-founder Alex Kendall, the unicorn is one of London’s biggest success stories.
“Ten years ago, building a frontier AI company from London felt like an unusual choice,” Kendall told me. “Now it feels like an obvious one.” Wayve moved into King’s Cross in 2018 looking for a space that could double as a garage — “a rare combination in Central London,” Kendall said. He has watched the ecosystem mature around him — and it’s now evident that a startup can stay in London, raise serious capital, hire world-class AI talent, and remain globally competitive, he said. Down the street from Anthropic’s new 158,000-square-foot office is the AI agent builder Sierra and the AI video platform Synthesia.
Laura Gonzalez Florez, Synthesia’s chief of staff and head of people, says the company moved into its glossy new office building a year ago to accommodate its growing team. They were drawn to the area for the same reason as everyone else: “It’s very close to the airport … very close to where a lot of investors are,” she said.
Image Credits:Synthesia
Around two-thirds of Synthesia’s engineers are remote, Gonzalez Florez said, letting the company tap into an affordable, international, and diverse talent pool and helping it scale faster. “From London, we can hire and work, without any problem, people from anywhere, from Slovenia to Portugal,” she said.
Unsurprisingly, London’s AI boom is also causing a talent war.U.K. AI job postings have skyrocketed in the past few years, per data from PwC. When Anthropic announced it moved into town earlier this year, it listed, for example, a salary range of £260,000 to £630,000 for a machine learning research engineer when the average salary in London for the same role is around £102,000. Some founders in the U.K., like those in Silicon Valley, are being forced to raise more and bigger rounds to keep up.
“The real test is whether more globally significant AI companies are founded, funded, and scaled from the U.K., while continuing to attract the world’s best talent to build them here,” Zain Ali, founder of the King’s Cross-based AI legal firm Centuro, told me. “If that continues to happen, King’s Cross won’t just be an AI hub. It’ll become one of the U.K.’s most important strategic assets.”
When you purchase through links in our articles, we may earn a small commission. This doesn’t affect our editorial independence.#Thisformernotorious #redlight #districtis #nowone #worlds #top #hubs #TechCrunchUK This former notorious red-light district is now one of the world’s top AI hubs | TechCrunch
What every U.K. AI startup wants to know these days is, how can I get office space in King’s Cross?
The area is so hot that a VC firm allegedly recently won a deal by promising a founder office space in the neighborhood. “We stop at nothing to win deals [for] and to support” founders, “including helping them source office space when needed,” the firm told me when asked about the rumor, declining to confirm or deny any details.
The neighborhood’s popularity began back in 2016 when DeepMind — then newly acquired by Google — moved in. Soon after, a flood of AI startups followed, wanting to be around the Google DeepMind magic. Today, they hope to take advantage of the cluster of AI talent there.
This has transformed King’s Cross into one of the world’s top AI hubs, rivaled only by San Francisco and Beijing. Around London, it’s known by the sobriquet “Knowledge Quarter,” as it’s home to names like OpenAI, Meta, Isomorphic Labs, Cusp AI, Wayne, Recursive, and, a little farther down the road, Synthesia and Anthropic. The European Technology Network (ETN) just moved into a glossy new office nearby, while University College London sits around the corner.
Mixed in with the new developments are trendy food spots like Hoppers and BAO. Hop a train from King’s Cross, and founders can be in Cambridge in 45 minutes to source talent or can be in Paris in two hours to strike a deal.
Who would have guessed that a little more than 20 years ago, this was one of the seediest areas in London?
“In the ’80s, crack and heroin made the area a major narcotics market,” Hussein Kanji, an investor at Hoxton Ventures, said, recalling syringes in tree trunks and gangs patrolling the streets. “In 1982, the local church was occupied by the English Collective of Prostitutes for 12 straight days.” Then, in the early 2000s, a real estate developer had a dream and, well, “now it is the AI hotbed of the United Kingdom,” Kanji said. “What a change.” Around 18 months ago, his portfolio company BioCorteX moved from the neighborhood Holborn to the Jellicoe building in King’s Cross, hoping to be near the action. “Lots going on in London right now,” Nik Sharma, co-founder of BioCorteX, told me. “Lots of hyperscalers moving in.” That includes, reportedly, Jeff Bezos’ AI company Prometheus, which is also said to be in talks to move into the Jellicoe.
There are around 3,600 AI startups in London, which, together, have raised around .1 billion out of the .8 billion raised in the city since late July, according to Dealroom. Since the start of June, AI-related startups have leased more than 1 million square feet of office space in London, according to the real estate firm Knight Frank. With that, prime rents in King’s Cross have risen 18% over the past three years, Chris Dunn, a commercial insight associate at the firm, told me. That percentage represents only the largest leases encompassing at least 10,000 square feet, like the ones OpenAI and Prometheus are signing. The shorter deals go for even more, he said, and now the vacancy rate for conventional office space is just 0.9%. “Demand has outstripped supply,” he continued.
Today, one of the big topics of the area is sovereignty. It was a wake-up call for many when Anthropic shut off access to Mythos and Fable this summer, leaving some in the ecosystem to conclude: “We’d better look after ourselves,” Saul Klein, co-founder of the VC firm Phoenix Court, told me.
Phoenix Court is located in the King’s Cross area and has three portfolio companies in the vicinity, including Olix (which just announced a .3 billion valuation), Early Health and CoMind. Robin Klein, co-founder of the firm, said the shutdown of Fable and Mythos access was a “small but sharp reminder that Europe can’t simply rent its AI capabilities and capacity; it needs to build and hold some of its own.” King’s Cross, he said, is where much of this building is actually happening.
“The bigger question,” he continued, “is whether the U.K. builds the infrastructure, compute, energy, capital, to make this self-reliance durable, rather than just hosting outposts of U.S. labs.”
Image Credits:Phoenix Court
Top founders want to stay
Simon Kohl, founder of Latent Labs, has offices in King’s Cross and San Francisco. The London office, at the moment, is growing faster, and he’s more bullish than ever on the ecosystem, he said. “The mood right now feels less like London trying to catch up and more like London becoming one of the default places to start a serious AI company,” he said. Look around and you are likely to see Wayve testing its autonomous cars. Founded in 2017 by co-founder Alex Kendall, the unicorn is one of London’s biggest success stories.
“Ten years ago, building a frontier AI company from London felt like an unusual choice,” Kendall told me. “Now it feels like an obvious one.” Wayve moved into King’s Cross in 2018 looking for a space that could double as a garage — “a rare combination in Central London,” Kendall said. He has watched the ecosystem mature around him — and it’s now evident that a startup can stay in London, raise serious capital, hire world-class AI talent, and remain globally competitive, he said. Down the street from Anthropic’s new 158,000-square-foot office is the AI agent builder Sierra and the AI video platform Synthesia.
Laura Gonzalez Florez, Synthesia’s chief of staff and head of people, says the company moved into its glossy new office building a year ago to accommodate its growing team. They were drawn to the area for the same reason as everyone else: “It’s very close to the airport … very close to where a lot of investors are,” she said.
Image Credits:Synthesia
Around two-thirds of Synthesia’s engineers are remote, Gonzalez Florez said, letting the company tap into an affordable, international, and diverse talent pool and helping it scale faster. “From London, we can hire and work, without any problem, people from anywhere, from Slovenia to Portugal,” she said.
Unsurprisingly, London’s AI boom is also causing a talent war.U.K. AI job postings have skyrocketed in the past few years, per data from PwC. When Anthropic announced it moved into town earlier this year, it listed, for example, a salary range of £260,000 to £630,000 for a machine learning research engineer when the average salary in London for the same role is around £102,000. Some founders in the U.K., like those in Silicon Valley, are being forced to raise more and bigger rounds to keep up.
“The real test is whether more globally significant AI companies are founded, funded, and scaled from the U.K., while continuing to attract the world’s best talent to build them here,” Zain Ali, founder of the King’s Cross-based AI legal firm Centuro, told me. “If that continues to happen, King’s Cross won’t just be an AI hub. It’ll become one of the U.K.’s most important strategic assets.”
When you purchase through links in our articles, we may earn a small commission. This doesn’t affect our editorial independence.#Thisformernotorious #redlight #districtis #nowone #worlds #top #hubs #TechCrunchUK](https://techcrunch.com/wp-content/uploads/2026/08/DM9A2852.jpg?w=680)

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