Thrash soon began to evolve and split into more extreme metal genres. "Slayer's music was directly responsible for the rise of death metal," according to MTV News. The NWOBHM band Venom was also an important progenitor. The death metal movement in both North America and Europe adopted and emphasized the elements of blasphemy and diabolism employed by such acts. Florida's Death and the Bay Area's Possessed are recognized as seminal bands in the style. Both groups have been credited with inspiring the subgenre's name, the latter via its 1984 demo Death Metal and the song "Death Metal," from its 1985 debut album Seven Churches (1985).

Death metal utilizes the speed and aggression of both thrash and hardcore, fused with lyrics preoccupied with Z-grade slasher movie violence and Satanism. Death metal vocals are typically bleak, involving guttural "death growls," high-pitched screaming, the "death rasp," and other uncommon techniques. Complementing the deep, aggressive vocal style are downtuned, highly distorted guitars and extremely fast percussion, often with rapid double bass drumming and "wall of sound"–style blast beats. Frequent tempo and time signature changes and syncopation are also typical.

Death metal, like thrash metal, generally rejects the theatrics of earlier metal styles, opting instead for an everyday look of ripped jeans and plain leather jackets. One major exception to this rule was Deicide's Glen Benton, who branded an inverted cross on his forehead and wore armor on stage. Morbid Angel adopted neo-fascist imagery. These two bands, along with Death and Obituary, were leaders of the major death metal scene that emerged in Florida in the mid-1980s.
In the UK, the related style of grindcore, led by bands such as Napalm Death and Extreme Noise Terror, emerged out of the anarcho-punk movement. A large Scandinavian death metal scene, with bands such as Sweden's Entombed and Dismember, began to develop as well. Out of this evolved a melodic death metal sound, typified by Swedish bands such as In Flames and Dark Tranquillity and Finland's Children of Bodom and Kalmah.