Although not Death Metal themselves Slaughter gets that classification for its influence on that genre years later.
Slaughter was a cult Canadian pre-Death Metal band featuring Dave Hewson (vocals/guitar), Terry Sadler (vocals/bass) and Ron Sumners (drums) that attracted a small but strong following through their short career. Formed in 1984, the band went the usual demo tape route at a time when underground tape trading was rampant and served to heighten band awareness, eventually recording their Strappado album in 1986, a simplistic album but one nonetheless that would later influence the Death Metal scene a few year's later. Before the follow-up Paranormal could be released for 1990, however, the band broke up during the recording phase. Strappado would later be re-released along with some demo material, but Paranormal was never released. Guitarist Dave Hewson went on with a new line-up under the name Strappado (the name change both to indicate a new direction and to avoid conflicts with the U.S. Glam band Slaughter that was now on the rise), but they never progressed beyond demos. Later, Hewson and Bobby Sadzak (one of the new Strappado members) formed Inner Thought, a going concern for a few years before it too folded in 1996. Slaughter (or the remains there-of) would have one last blast of fame with their last recording being a song for a Celtic Frost tribute in 1994.
Footnote: Do not confuse this act with the U.S. Glam Metal act of the same name.