In the 30-plus years since Per Ohlin first donned corpse paint, black metal has mutated, evolved, and adapted to so many different environments and subcultures, it can feel like an invasive species set loose on a fertile world. In theory, this is strikingly rigid music—in the trad black metal that looks to Norway’s second wave, at least, there is no swing, there are no bent notes, and the emotional palette is as monochromatic as the album covers—but it’s proven itself to be surprisingly flexible. So when bands like Dimmu Borgir bring a full orchestra on stage, or Cradle of Filth collaborate with Ed Sheeran, there’s a strength in choosing to remain within the genre’s confines, playing trad black metal, and absolutely ripping shit up.