The lead voice actor in global box office smash Demon Slayer: Kimetsu no Yaiba Infinity Castle says he’s been “blown away” by the anime film’s success.

Based on a 2016 manga series, the film is the first part of a trilogy that caps off the story of an enormously popular animated TV series launched in 2019.

It follows the story of teenager Tanjiro Kamado, who joins a team of demon hunters after his sister is turned into one.

Zach Aguilar, who plays Tanjiro in the English language version, tells BBC Newsbeat the success of the film shows the series has become a full-on “pop culture phenomenon”.

Since its release, Infinity Castle has taken more than $600m (£447m) at the worldwide box office, putting it ahead of Mission Impossible and Fantastic Four in this year’s top 10.

It hit the number one spot in its first week in Japan and the US, and was only kept off the top in the UK by Downton Abbey: The Grand Finale.

Zach, 27, who has lent his voice to dozens of video games and anime titles, tells Newsbeat anime “has slowly been on this track to reaching mainstream popularity”.

He thinks Inifinity Castle is the title that pushed it over the line.

“I just think it’s so freaking cool to have anime be this mainstream thing and Demon Slayer be the backbone of that,” he says.

Rahul Purini, president of streaming service Crunchyroll, told the BBC earlier this year that anime was “one of the fastest-growing entertainment sectors” in the world.

He said it owes its popularity to the many sub-genres and styles that exist within the medium.

“What makes anime for us is that it is authentically conceived and created in Japan,” he said.

“It is a very unique storytelling format, and it has not only stunning visuals, but strong characters, very unique storytelling that’s set in these amazing worlds, and that’s what attracts fans to these stories.”

The company estimates there are 1.5 billion “anime-curious” fans around the world who are finding it easier to access popular shows as streamers such as Crunchyroll and Netflix add them to their services.

Zach says it can be a lot of pressure to portray a role such as Tanjiro, who he describes as “the hardest character” he has ever had to portray.

“I draw from my own personal hardships and pour some of that into Tanjiro,” he tells Newsbeat.

“There are times when I feel like I’m physically going through that pain.”

Demon Slayer is made in Japan, initially written for and recorded by Japanese actors.

Zach says that can be a challenge for those like him who provide foreign-language dubs, especially when it comes to matching animations to voices.

“If a scream is ten seconds exactly and you do ten and a half, that’s too long,” he says.

“And you have to do it again.”

Voice actors rarely record with their co-stars, says Zach, so it’s down to him to imagine what others are doing in a scene for his own lines to “make emotional sense”.

“It is a niche skill, having that imagination,” he says.

“You don’t get to be on a set with all these props and things to play off, you have to really imagine that world in your head.

“If you are running through a scene you can’t physically run – you have to make that scene in your head and make it natural.”

Zach, whose love of anime drew him to voice acting, says he hopes the success of Infinity Castle will inspire people to dive further into what the genre has to offer.

“You’ve got to give anime a shot, you don’t know what you’re missing,” he says.

“It has some of the greatest storytelling I’ve ever experienced.”

But how much time he’ll have to spend watching it himself is up for debate. He’s signed up for parts two and three of the Demon Slayer trilogy.

“This first one’s already blown my mind,” he says.

“I cant even imagine the second and third one – it’s going to be insane.

“It’s only going to get bigger and bigger from here on out.”

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