Neurosis emerged as a hardcore punk band, performing a blend of hardcore and heavy metal inspired by British punk and described as crust punk or crossover. However, their second album "The Word as Law" (1990), introduced some elements of avant-garde music and sludge metal, a genre which was emerging as a fusion of hardcore and doom metal. Thereafter, the band developed a unique sound; Greg Moffitt of the BBC wrote that through a "process of evolution and refinement" beginning with "Souls at Zero" (1992) and culminating in "Through Silver in Blood" (1996), they "heavy music to previously unimaginable spaces and, in the process, shape[d what has thus far been metal's definitive response to the 21st century."