Metal may have the heart of a rebellious teenager (and keep it in a jar in the basement), but in 2014 it had the face of a grizzled vet. It was a year of comebacks: from Slipknot to At the Gates, from Godflesh to Behemoth, whose leader Nergal fought off cancer to hail Satan in song once again. It was a year when wizened electric wizards rocking low and slow (Yob, Crowbar, SunnO))), Ommadon, et al.) crawled by the fast and the furious on the path to ascend. Grunge pioneers, avant-garde longtimers, and even a hip-hop O.G. got in on the metallurgy and made magic. But anyone under the age of, say, 30? Not as much. So study up, young'uns, and respect your elders: Here are heavy music's 20 best of 2014.