Demon Slayer star says anime film's success is mind-blowing

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.

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."

Listen to Newsbeat live at 12:45 and 17:45 weekdays - or listen back here.