‘The plague, the apocalypse and the imminent death and destruction of our lives”: that is how Tobias Forge, the mastermind behind the Swedish band Ghost, describes their latest album, Prequelle. He thinks it may be the first positive record to be written about the Black Death. “The plague of the 1300s was a big killer which wiped out half of the European population and caused insurmountable trauma for the survivors,” he says. “But, in the midst of all this chaos and destruction, it caused a lot of regrowth – I’ve always found that very inspiring.”

Until last year, Forge and the rest of the band were anonymous. If our interview had been conducted when any of Ghost’s previous full-length albums were released – Opus Eponymous (2011), Infestissumam (2013) or Meliora (2015) – Forge would have been incognito, dressed as one of the demonic masked figures, or “Nameless Ghouls”, that make up Ghost’s sinister backing band. Theories were rife, but, until 2017, no one knew who any of the band members were – rumours persist that Dave Grohl played with them live on several occasions – and all the songs are credited to a Nameless Ghoul.

Then, in April 2017, four former band members filed a lawsuit against Forge, claiming he had taken control of business affairs without input from anyone else; Forge countered that Ghost has always been his project and that the other members were paid a salary, essentially acting as his backing band. Forge was forced to emerge from the occult enigma he had hidden behind since 2006 and reveal his true identity.

“With hindsight, I think the reveal didn’t really damage the band as negatively as the intention behind it [the lawsuit],” says an unmasked and softly spoken Forge. “I had to go through a little bit of surgery when it came to my social life,” he says (the lawsuit is ongoing). “A lot of the decisions that I made were based on trying to accommodate people’s wishes, trying to be a friend and set them up for life. That intention seems to have been turned into me trying to fuck people over. That feels like a betrayal because this was not done out of spite at all.” Despite the legal action from his former friends, he is philosophical. “I took it almost as an acknowledgment that I must be doing something right. If things were going down the fucking tubes, no one would care.”

Apart from the lawsuit, things are going very well for Ghost. In 2016, the band won a Grammy in the best metal performance category for Meliora’s lead single, Cirice; a new single, Rats, has racked up more than 7m YouTube views; Prequelle has been released to strong reviews; and Forge will finally be able to realise his ambitions for the band’s live shows in December when Ghost play two 20,000-capacity gigs on the east and west coasts of the US. In the UK, the band were last seen headlining a sold-out 2,000 capacity Forum in London, but they dominate conversations of potential future headliners for this weekend’s Download, by far and away the UK’s largest metal festival.

“My aim is absolutely to fill those large stages,” Forge says. “Unfortunately, most bands don’t do that. I’m not saying that they’re not good enough necessarily, but what they bring in terms of performance is not big enough. If we want to have a rock culture where we go to wide-open spaces and see larger-than-life spectacle, then bands need to step up. We need to put a little faith into the teenagers that are forming bands now; it takes more than a stack of Marshalls to get a big rock crowd enthusiastic these days.”

Ghost’s religious iconography has captured the imagination of the extreme metal crowd, but the band have more in common musically with the psychedelic prog-rock stylings of Blue Öyster Cult than the apoplectic black metal maelstrom of, say, Bathory. Ghost’s use of occult visuals has led to misunderstandings, particularly in the US: Forge maintains that they use this imagery because “it looks awesome” rather than because they are trying to send middle American children to hell.

Forge maintains that Ghost isn’t mocking the church, but rather mimicking some of its rituals. “A rock concert fulfils the same service that church can provide,” he says. “It puts people in an environment that is greater than themselves.” As we talk, he debates the merits of organised religion with himself. “You have to be in the favour of this condemning God who could throw you down to hell, and it’s this that makes especially linear religions so dangerous because it’s always looking up and kicking down,” he says. “Even the architecture – churches were regarded as unearthly because they were so imposing. They combined threat with inclusion and salvation.” He thinks again. “But then there is a lot to learn from the church. Not everyone going to service does that as a way of hypocritically fooling someone. Most people try to look after themselves and their own and are trying to do things the way that they see fit.”

Facebook Twitter Pinterest Papa Emeritus – another likely Forge alter ego – on stage. Photograph: Alamy

Each album has seen subtle variations in the Ghost aesthetic, with three different iterations of a sinister pope figure, Papa Emeritus – widely believed to be Forge – fronting the band while flanked by the revolving lineup of Nameless Ghouls. But Prequelle involves the biggest visual and thematic shift. A series of tongue-in-cheek videos introduced the newly appointed, sharp-suited Cardinal Copia – again, likely to be Forge – who now leads the congregation in lieu of Papa Emeritus. But the Papa lineage is still represented in the form of the frail, ageing Papa Nihil, who has a gloriously over-the-top saxophone solo. “I’m a big fan of the sax as an ingredient,” says Forge, who has played most of the instruments on Ghost’s albums. “It is Americana for me. It’s Cheers and baseball and Dodge cars, filtered through rock’n’roll. When I hear a sax, I think of Bruce Springsteen headlining a big outdoor stadium in 1985 and the sweat is just fucking pouring, and everybody’s happy.”

Prequelle approaches its weighty subject matter with joy and a vaudevillian theatricality, married to huge guitars and the pop sensibility of the Beatles, Depeche Mode and Abba – all of whom Ghost have covered. Songs such as Dance Macabre and See the Light contain some of the band’s catchiest choruses yet, so Forge’s quiet optimism and ambition is understandable. “There seem to be some reservations about bringing spectacle to the rock world, but we’re happy to fill that void,” he says. “Bands need to be larger than life and that’s something that I’m not able to do as Tobias. But I think we do a very good job as Ghost.”

Prequelle is out now on Loma Vista