Regarded as important, landmark figures in the development of European heavy metal, Swiss trio Celtic Frost turned their hand to a number of different styles within the genre and left a sprawling legacy of work that later influenced Napalm Death, Nirvana and Sepultura. Front man Tom Warrior groomed his guttural growls as part of seminal death metal thrashers Hellhammer in the early 1980s, but when their ragged, primitive spirit became too limited, he formed Celtic Frost with bassist Martin Eric Ain and later recruited drummer Reed St. Mark. The apocalyptic, bombastic sound of second album 'To Mega Therion' helped pioneer the sound of 'black metal', but the band quickly evolved and played with grinding, industrial menace and raw, gothic ballads on their avant-garde metal masterpiece 'Into the Pandemonium' in 1987. After Ain and St. Mark left the group, a surprising attempt at glossy, chart-friendly stadium rock on 'Cold Lake' was widely panned by critics and fans, and despite a return to form on follow-up 'Vanity/Nemesis' they split in 1993. Fischer went on to form Apollyon Sun, but the band reformed in 2001 and went on to release sixth album 'Monotheist' and undertake their biggest ever tours of Europe, America and Canada. In 2008 they announced their official split.