With technical proficiency to spare, L.A.’s Exmortus might also be the most devoted to turning centuries-old classical themes into thrashing death metal. Jadran “Conan” Gonzales and David Rivera have some of the fastest fretboard fingers on the planet, and their mind-blowing chops are the main reason this band exists—although inspiring warriors to brandish swords against tyranny, as lyrics to “Relentless,” “For the Horde,” and “Death to Tyrants” command, may run a close second. “Appassionata,” which interprets Beethoven at lightning speed, needs no words at all.