CASTLE Not pictured: Nathan Fillion. COURTESY CASTLE/VÁN RECORDS

FOR THREE ALBUMS, Castle chose to cloak itself in darkness. The California heavy metal trio’s 2011 debut, In Witch Order, depicts a strangely unsettling image of sheep on the cover. Its opening track, “Descent of Man,” sets the band’s tone, pitting bassist Liz Blackwell’s dulcet snarl against a buzzy thicket of guitars.

2012’s Blacklands features heavier riffs, stronger melodies, and song titles like “Corpse Candles.” The cover art? A mystical Denis Forkas Kostromitin painting of a woman, a child, candles, and ominous smoke rising from a mountaintop.

Forkas’ work returned on the cover of 2014’s Under Siege, this time with children exploring a disemboweled bovine creature. Eighty seconds into the album’s lead single, “Temple of the Lost,” a strangled, demonic voice declares: “Quest for fire, power from below. Reaching through forever, but never in control.”

Since forming in San Francisco six years ago, Castle has established itself as one of the most reliable dealers of throwback thrash, doom, and heavy metal around, thanks not only to its rock-solid recorded output, but also a relentless tour schedule. But when it came time to make a fourth record, Blackwell and her guitarist/husband Mat Davis found themselves in Los Angeles, and letting in just a sliver of light.

Their circumstances—living in a small apartment in a sprawling city—influenced Castle’s July release, Welcome to the Graveyard, which also happens to be the band’s first release to feature the (admittedly shadowy) faces of Blackwell and Davis on the cover.

“Los Angeles is a very particular place,” Davis says. “I always get a certain feeling after I’ve been there for a while, and we were there for a year, so it had definitely sunk in. There’s kind of a high level of... paranoia or something going on there. It’s a pretty intense place, from intense sunshine to helicopters flying overhead. It’s in there, the undercurrent [of the city].”

On Graveyard, Davis rolls out his usual arsenal of riffs, and drummer Al McCartney thunders accordingly. But the dense layers of guitars from previous Castle albums have thinned a bit, giving Blackwell’s vocal melodies room to tower and thrill. The result sounds something like Heart’s Ann Wilson fronting Pentagram.

The songs on Graveyard were written at home in LA on an acoustic guitar—a method Davis says they’d never tried before.

“Rather than renting a jam room and cranking up amps, we were just in our apartment playing late at night,” he says. “It’s cool that it happened like that, because some of the melodies came first. We’d stumble upon something we thought was really cool and then we’d start to build on it.”

That process led to the record’s stripped-down sound, as well as a new appreciation for how real life can’t help but shape art.

“By staying open to whatever comes your way, I think the music is going to be a little bit more of a reflection of where you’re at in your life,” Davis says.

He’d stumbled upon Castle after years spent writing and recording mostly instrumental music, but struggling to find people to play it with him. That changed when he met Blackwell, a powerful vocalist and commanding stage presence. Davis credits her “raw talent” for making Castle a reality.

“Liz is really the catalyst for the band,” he says. “She kind of brought it from somewhere in my head and strictly a studio project to collaborating with someone. It took on a life of its own. There was no grand design. But once we got our foot in the door, Liz and I were just like fish to water [as far as] traveling and playing music, and being able to do that together.”