Formed in August 1990, Monstrosity burst onto the scene with their explosive demo Horror Infinity, which gained traction through the global underground tape-trading network.

This led to their debut album, Imperial Doom (1992), with Nuclear Blast, followed by extensive touring across Europe, Mexico, and the U.S., supporting acts like Pantera, Deicide, Overkill, and Pestilence. Their second album, Millennium (1996), released under Conquest Music Inc., marked a significant milestone in their career, broadening their audience through extensive tours across the United States and Latin America, including notable performances in Peru and Colombia.

These efforts solidified their growing international presence and established them as a formidable force in the heavy metal scene. Millennium showcased a refined sound, blending raw aggression with intricate instrumentation, produced by Scott Burns, which resonated deeply with fans and critics alike. However, the album also marked a pivotal transition for the band, as it was the final record to feature their original vocalist, George "Corpsegrinder" Fisher. Following his departure, Fisher achieved widespread acclaim as the frontman for the genre-defining death metal band Cannibal Corpse.