Celtic Frost's impact on the evolution of European heavy metal cannot be overstated. Along with power metal kings Helloween (and to a lesser degree, the sometimes cartoonish Mercyful Fate), Frost's enduring influence on Europe's heavy metal landscape is arguably comparable to Metallica's standing in America. Labeled by critics as "avant-garde" for their radical fusion of violent black metal and elements of classical music, the band represented a distinctly European metal perspective. But their history was troubled, their output uneven to say the least, and their ignominious end hardly fitting of their important legacy.