We know today that there are a ton of different subgenres of metal, some so obscure that they need to be explained. But it wasn't always this way.

Metal didn't really start splintering off until the very late 1970s and early '80s. Bands like Venom, Iron Maiden and Motorhead all sounded so different from each other that it seemed impossible lumping them into the same category. These three bands were all major influences on the development of thrash, which is sort of where the lines start to fade even more.

Slayer was one of the "Big Four" thrash bands who rose to popularity in the early '80s, but they really didn't sound anything like Metallica, Megadeth or Anthrax. They were much more aggressive, and primarily writing songs about much more graphic subjects such as war, Satanism and destruction. Their third and most critically acclaimed album Reign in Blood is considered by many to be the true blueprint for what eventually became death metal, but that didn't come out until 1986.

The chaos had already started brewing years earlier, with bands like Dark Angel and Possessed, and also Kreator over in Germany. We were hearing new vocal styles — gutturals — and even deeper-tuned guitar licks than ever before.

Scroll below to see 11 bands considered pioneers of death metal.

Best Death Metal Album of Each Year Since 1985