No classical instrument is more metal than the cello. Something about the particular tonal qualities make the cello sound especially grim. So it only makes sense that cellist, Raphael Weinroth-Browne has taken to covering metal.
Mastodon's "Blood and Thunder" is Weinroth-Browne's latest cover and the end result is great. If you want to check out other equally impressive covers of Opeth and Lamb of God check out Raphael's YouTube Channel.