 Death metal developed out of thrash, particularly influenced by the bands Venom and Slayer.Florida's Death and the Bay Area's Possessed emphasized lyrical elements of blasphemy, diabolism and millenarianism, with vocals usually delivered as guttural "death growls," high-pitched screaming, complemented by downtuned, highly distorted guitars and extremely fast double bass percussion.Black metal, again influenced by Venom and pioneered by Denmark's Mercyful Fate, Switzerland's Hellhammer and Celtic Frost, and Sweden's Bathory, had many similarities in sound to death metal, but was often intentionally lo-fi in production and placed greater emphasis on satanic and pagan themes.