Like thousands of other music fans, Lani Hernandez-David will be watching Sleep Token at Download Festival this weekend.

But unlike the rest, the 22-year-old can lay a claim to playing a role in the headline act’s meteoric rise.

The rockers have recently had their first number one album and have developed a huge following with breakout viral hits – all while remaining anonymous behind custom-designed masks.

And Lani is the one who’s created some of them.

He works out of a small studio in south London and has been into making masks and costumes since he was about 11.

His first latex creation still sits on his workbench.

Fuelled by his interest in cosplay, he says he refined his skills by watching YouTube tutorials and eventually began posting his own creations online.

Sleep Token’s drummer spotted them, and dropped Lani a DM asking if he’d like to work for the band.

“I thought it was a scam at first,” he says.

But rock fan Lani said he noticed the profile’s blue verification tick, and recalled that he’d actually been to see Sleep Token at a festival months earlier.

Then the penny dropped.

“Oh, this is that band I saw,” he says.

Lani met the band, who provided him with ideas for designs, and he started the nerve-wracking task of creating them.

“I’d never made masks for a touring band before, ” he says.

Sleep Token debuted his creations at their sold-out Wembley show in 2023, a moment Lani says he won’t forget.

“When they came out wearing my masks I just pinched myself,” he tells BBC Newsbeat.

“I remember thinking: ‘That was made on my kitchen table – that’s insane’.”

Lani, who still has a second job in a costume shop, has since been asked by other bands to make masks for them.

Whenever he’s approached, Lani says he will “binge all their music, watch all their interviews”.

“You never know what will inspire from the music, the lyrics, back into the mask-making,” he says.

“So I try to really involve myself with the artist just so I can get back in the zone.”

But Lani says he owes a lot to Sleep Token.

“That was my first one and I’ve learnt so much from meeting them.

“I’ve tried to incorporate that knowledge back into mask-making and just improving every time.”

Music journalist Emma Wilkes says part of Sleep Token’s appeal is in their “genre-bending” sound.

They are often described as a metal band but Emma says they also employ elements of “pop, R&B, a little bit of trap as well”.

Emma says the band has been on a “meteoric trajectory” since 2023 album Take Me Back to Eden, and viral hits that have propelled them “to a level of success at a speed nobody could have anticipated”.

Their latest album Even in Arcadia topped album charts but, more significantly, also generated a top 10 single.

But Sleep Token’s success has also generated negativity – especially among some long-time rock music fans.

One scathing review of their most recent album said it was “metal music for Disney adults”.

Emma says she’s surprised by the level of anger they sometimes attract.

“I can understand if people listen to it and they don’t quite understand it,” she says.

“It’s a bit different, it pulls influences from all over the place.

“If you don’t get it fair enough, but the sheer levels of vitriol, especially after this new album has come out, it’s quite astounding to me.”

One of the most common criticisms of Sleep Token is that their masks are a gimmick to generate attention.

Lani’s not so sure.

“They could make all of the music without the get-up and I think they’d still do well,” he says.

“But the lore, the ‘gimmick’, really helps.”

Sleep Token seem to have inspired other masked bands. President – probably the most high-profile recent example – are also set to play at Download this year.

“That’s good for people like me,” says Lani, who has also worked with President.

“Maybe too many people will do it one day but for now it’s great.”

Lani says his dream client would be Slipknot, the nu-metal band with nine masked members that provided a prototype for bands like Sleep Token.

But for now he’s content.

“I’m doing what I’ve always wanted to do,” he says.

“If you had told 14-year-old me I’d be making masks for bands I’d have told you ‘no way’.”

Now, he says, he’s known as “the guy that does the band masks”.

“Five years down the line hopefully I can work for myself and make more crazy silly stuff.”

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