“I’M NOT SURE I know the difference between heavy rock and heavy metal, but it is good to be known as inventors of heavy metal rather than followers,” says Terence Michael Joseph “Geezer” Butler, the original bass player and primary lyricist for the almighty Black Sabbath.

Butler is somewhat modest over email, but Black Sabbath’s influence on heavy metal, doom metal, black metal, and EVERY metal, really, is as immeasurable as outer space—they’re essentially the Beatles of all things heavy. Throughout their career, metal’s “Fab Four” gave music fans a paintbrush with endless colors to choose from and zero boundaries.

Butler, Ozzy Osbourne, Tony Iommi, and Bill Ward showed rock ’n’ roll enthusiasts the other side of the peace and love coin at a time when nobody wanted to look at it. Black Sabbath is solely responsible for injecting the darkness, the coarse edge, and the true heavy into rock ’n’ roll—an effort that, in turn, spawned metal. If anyone, even your own grandmother, tells you Led Zeppelin had a hand in it, you can tell them to fuck right off!

Black Sabbath has earned their right to the throne, but after releasing their 2013 Grammy-winning album 13 and embarking on one last tour they’ve aptly named “The End,” they are hanging up their crown. The kings are officially calling it quits. During our conversation, Butler laid out the logic behind their decision:

“We started thinking about it when Tony [Iommi] was diagnosed with lymphoma. We realized we weren’t going to be around forever, and the 13 tour was quite a short tour,” he said. “So, we decided to do one last tour while everyone was healthy enough, and while we were at the top of our game. It will be sad to end it all, [but] it has to finish sometime.”

This may be the end for Sabbath as a whole, but banking on solo projects is certainly a safe bet. Ozzy has already said (and sung) that he “don’t wanna stop,” and those who understand what Iommi is capable of know there’s gotta be endless amounts of material stashed away somewhere. It wouldn’t make sense for the “Hand of Doom” to just rest on his laurels, anyway. 

Butler confirmed all of these suspicions, and claims he has plans of his own.

“I’ll be working on solo stuff since I’m always writing, but I don’t have any specific details yet. I’m sure Tony will have lots of things going. He must have hundreds of riffs lying around. When we were writing the album 13, Tony had about 70 riffs left over. All of them gems.”

As tragic as it may seem, Black Sabbath lowering their scepter isn’t that sad at all—how could it be? They’ve produced more brilliance in their tenure than 100 bands could produce in the next 1000 years. If the opening track of their debut album didn’t snap the axis of your world the first time you heard it, whether it was 1970 or present day, you’re not from this planet. Black Sabbath will be a towering monolith of inspiration and importance until sound ceases to travel. Butler may have had a modest tone in his responses, but he also seems to know what they’ve done is magic.

“I am happy with the band’s legacy,” he says. “Of course there could be regrets, but I think things happen for a reason. So with that in mind, I can’t really have any regrets.”