The band group I picked to use as an example is a band named Oblivion [1984-85], R.A.V.A.G.E. [aka Raging Atheists Vowing A Gory End, 1985-88]
You can click on R.A.V.A.G.E to learn more about them.
Some information on this be as atheist are a technical death metal band from Florida. They created highly complex music with heavy guitar riffs and multiple time changes within each song. Unlike many complex prog bands however they limited their tracks to around the 4 minute mark. Death of bassist Roger Patterson in a motor accident in 1991 just as they were preparing to record their second album, Unquestionable Presence, led to a delay which eventually resulted in Tony Choy being recruited on bass. Roger's death, however, had a big impact on the band, especially drummer Steve Flynn, who quit shortly afterwards. Atheist already broke up for a short time in 1992 but re-formed in 1993, just to record their third album Elements due to the contract with their record label.