Black Sabbath

Distorted blues made heavier by late 60s British amplifications and tuned down a step to help Iommi with his hand issue, that's how metal was born. But they managed to ride that new genre, becoming its absolute masters and even evolving with superlative albums like Vol 4 and Sabbath Bloody Sabbath, imitated by all but unmatched in power and heaviness. Legendary also thanks to the figure of Ozzy, one of the greatest rock bands of all time, both in terms of quality.