Carnivore is an American crossover / thrash metal band from Brooklyn, New York founded by singer and bassist Peter Steele, and was formed out of the breakup of the Brooklyn metal group Fallout in 1982.
The first Carnivore album was heavily influenced by the contemporary New York metal scene. It also drew inspiration from Black Sabbath and early Judas Priest, whereas the second album had significant crossover influences. The "post-apocalyptic" theme that dominated the first album and was carried onto parts of the second album was apparently inspired by a dream Pete Steele had and which became the basis for the lyrics of "Predator", the first song from the original album.
The lyrical theme was then expanded on to describe human society (or the lack of one) between imaginary World Wars III, IV and possibly V (as referenced in the song "World Wars III & IV").