Doom metal is an extreme subgenre of heavy metal music that emerged during the former half of the 1980s. Generally, doom metal features very slow tempos, low-tuned guitars and a much "denser" or "heavier" sound than other metal genres. Both the music and the lyrics intend to evoke a sense of dread or impending doom, and often an atmosphere of despair.

Musically, doom metal is strongly influenced by the early work of Black Sabbath. A number of their early songs, such as "Black Sabbath" and "Into the Void" are considered embryonic or prototypical doom metal songs. Their third album, Master of Reality (released in 1971), features Tony Iommi's guitar and Geezer Butler's bass tuned down to C# for heavier riffing and reduced string tension for Iommi's previously injured fingers.