“Metal has again become that rebellious thing,” says Matt Young of Warner Music. "It’s gone away and gotten dangerous again."

Leave it to Game of Thrones, a series whose epic medieval battles and dragon-fire iconography echo classic heavy metal motifs, to accurately depict the once-prominent genre’s status in pop culture today.

Watchers of the show will recall this year’s most overt celebrity cameo: Ed Sheeran, who appeared — with no alterations to his real-world appearance, maybe a haircut — as a Lannister soldier with singing and speaking parts in a scene that lasted a whopping four minutes. Akin to his ubiquity just about everywhere else, you couldn’t miss the megastar in Westeros.

But few would have spotted the second musical guest Thrones slipped in this summer: the metal band Mastodon, who blended in as faceless, trudging members of the Night King’s army of the dead. No spotlight was given to the Atlanta prog-thrashers, just a quick “hey, was that...I think it was!” Easter egg for crossover fans.

The positioning was perfect. Of course the Mastodon guys were cast as trio of re-animated corpses, left to rot behind a wall that seals them from civilization — that’s been heavy metal’s relationship to the mainstream for nearly a generation now. You don’t find it unless you’re looking for it.

Following the early '00s -- where metal saw a spike in notoriety, as rap-metal hybrids like Linkin Park and Limp Bizkit popped up on TRL and more nuanced metal-leaning groups like System of a Down and Deftones were in MTV’s regular rotation -- the genre has largely been scrubbed from hit radio, and relegated to specialty stations and niche circles. Now, in 2017, the pop zeitgeist is so bereft of guitar music of any sort that it’s difficult to imagine a time when bands following Metallica’s blueprint — or even pleasing hair-metal-ers Bon Jovi or Motley Crue — might commercially dominate once more.

Yet the culture behind the jams somehow thrashes on. In the U.S., heavy metal has developed a dichotomous presence in recent years, where the music itself provides virtually no influence, yet the genre’s visibility in merchandising and live performance — especially from major artists who otherwise have no bearing in metal — is stronger than ever.

Just look to the artist of the moment, Taylor Swift, whose gothic cover for her approaching LP “Reputation” was mocked online as the advent of her black metal phase. To boot, the video for her single “Look What You Made Me Do,” the No.1 song on the Hot 100 right now, opens with her in full zombie makeup, crawling from a grave and then re-burying her human self. That feels a lot closer to, say, Avenged Sevenfold, than “All Too Well,” doesn’t it?

The list goes of superstars repping the heavy style goes on, from Justin Bieber’s Iron Maiden-inspired Purpose Tour merch to hip-hop, where the culture has bled deepest: see Kanye West rocking a Type O Negative shirt in the studio (lest we forget the Metallica-y Yeezus font); Travis Scott donning a Slayer t-shirt for his GQ magazine shoot (and riding a red-eyed, animatronic eagle on stage opening for Kendrick Lamar this year); and Lil Uzi Vert also swiping the Metallica typography for his mixtape Luv Is Rage. Then there’s the Marilyn Manson factor — LUV wears a diamond-encrusted pendant forged in the shock-rocker’s image, and Drake even had his dad pose for a photo with him. Further, during his Made in America set in Philadelphia Sept. 3 (and then again at Meadows in Queens, New York two weeks later), Jay-Z urged two circle pits in the crowd to conjoin and form one big unit of mayhem. 4:44? More like 6:66.

Remember when Aerosmith and Anthrax collaborated with Run DMC and Public Enemy to boost their own edge factors? The reverse now seems to be the prevailing trend.

“Metal has again become that rebellious thing,” says Matt Young, Executive Vice President of Warner Music Artist Services. “And it’s not the hair metal, it’s metal’s roots. You can see Iron Maiden shirts in H&M, their artwork is becoming iconic. It’s gone away and gotten dangerous again and that’s what makes it cool.”

The shift in dress from pop and hip-hop’s tastemakers — plus the ultra-influential Kardashians touting the clothes — has unsurprisingly trickled down to fans’ everyday wardrobe.

“When I was in high school, if you wore studded bracelets to school you’d get sent to the principal’s office,” says Missi Callazzo, co-owner of Megaforce Records, the label that first signed Metallica in 1983. “Now, spiked bracelets are high fashion. Every designer made biker jackets last year. … we had a metal T-shirt being sold in Fred Segal, it was crazy.”

Pop’s clearest proponent of thrash has been Lady Gaga, who not only performed with Metallica at the Grammys earlier this year (yes, a bum microphone ruined it, but the rehearsals were awesome) but injected some metal fuel into her current Joanne World Tour. Each night during “Perfect Illusion,” Gaga stands in black leather, her blonde hair blown out and moussed like Lita Ford, as she wails to a song that’s one double-bass blast beat away from morphing into an alt-metal bonanza, a la In This Moment or Butcher Babies.

“Lady Gaga has probably done more for metal in the last four years than anyone else,” Callazzo says. “Why are all these mainstream stores carrying these metal shirts? You can trace it back to her and her look and her aura of helping to exude all things metal.”

But does such a stylistic embrace mean heavy metal is on its way back to the musical conversation?

“I think there’s space for everything to be successful,” says Chris Brown, Vice President of Marketing for Roadrunner Records, which manages some of metal’s heaviest hitters including Slipknot and Killswitch Engage. “You see it on the touring side, like the Rock on the Range festival (in Columbus, Ohio) being such a success and selling out months in advance, with tens of thousands of people each day. It’s shows that the fans are, in fact, there.”

Though in terms of incoming listenership, Brown believes one of metal’s greatest obstacles to be the acceptance of streaming among diehard fans, who still cling to the genre’s more album-based format.

“It leads to people wanting vinyl or CD, and less of just listening to a single,” Brown says. “That mentality can exist with streaming and Spotify, I think it’s just an education process. Slowly it’s happening. Out of all the genres, rock feels like the one with the most room to grow, and once it starts catching up then people are going to rediscover it in some ways.”

Fans who do use streaming, however, are exceedingly committed to the genre. Spotify released data in 2015 that found metal fans to be the service’s “most loyal” listeners, based on a methodology that measured listening to the genre’s core bands.

But this isn’t necessarily a good sign for the music’s mainstream relevance. Metal has thrived for decades in part as an insular “you don’t know unless you know” scene, but if the genre is to again be appreciated for its superb musicianship and innate power, a few new bands will need to explode across the rock consciousness — the sort of Nirvana or blink-182 needle-moving moment that ensnares the counterculture. (It sure feels like people can use some monster tunes to scream along to these days.)

Young, Brown and Callazzo agree that Danish metal band Volbeat -- who topped the Mainstream Rock Songs chart twice this year with “Black Rose” and “The Devil’s Bleeding Crown” and opened for Metallica this spring -- is one act with heaps of crossover appeal.

“[Volbeat] has done a good job of taking in a lot of the history of rock and metal, but not making it inaccessible,” Callazzo says. “If you’ve become disillusioned [to the genre] and want to hop back in, they are a good entry point.”

Brown also sees a resurgence in hardcore punk, metal’s petulant cousin, with bands like Turnstile (Baltimore), Knocked Loose (Kentucky), and Angel Du$t (Maryland) hopping on national tours with proven acts like New Found Glory and Every Time I Die.

“There’s definitely energy and passion there, and it’s a fan base that is embracing streaming, and is listening to hardcore and hip-hop in the same day,” Brown says. “The new fan is going to help reshape the rock side of the industry.”

Until then, visibility in any form, from the French metal band Gojira scoring a Best Rock Album Grammy nomination this year, to Tool in June becoming the heaviest band to ever headline Governor’s Ball, down to the teens wearing Master of Puppets shirts in the suburbs, is a small step forward.

Says Callazzo: “If that girl walking down Fifth Avenue in an Iron Maiden shirt makes just one person go and listen to ‘Number of the Beast,’ I’ll take it.’”