Atlanta-based quartet Mastodon (guitarists Bill Kelliher and Brett Hinds, bassist/vocalist Troy Sanders, and drummer Bränn Dailor) has been quickly ascending the ranks as the best metal band in North America for the past five years, and new release Blood Mountain (2006) will likely solidify their position at the top. Situated as an alternative to the tedious snooze-metal of bands like Isis and Cult of Luna, Mastodon are furiously intense, brilliantly technical without being overly mathy, and capable of writing intelligent concept albums with subject matter ranging from obscure mythological creatures to Herman Melville’s Moby Dick. Musically, Blood Mountain is almost too good to fully take in one sitting: not a single riff is wasted, Dailor’s drumming is still unbelievable, and the production is more polished and varied, yet complements the music tremendously. Even if metal isn’t your teacup, you have to at least listen to why hundreds of thousands of metal fans are shitting themselves into a frenzy and haling the band as the second coming of (the anti-?) Christ.

There is a caveat, of course, which keeps Blood Mountain from being a perfect album, and it’s colossally significant. It isn’t my intention to swim against the tidal wave, but Mastodon seems to be hopelessly lost when it comes to the vocals. No longer content with the violent roars that characterized Remission (2003) (of which I loved), Sanders and Hinds mine from Ozzy power-balladry on “Sleeping Giant” to distorted, filter-swept Mike Patton yelps on “Bladecatcher.” One problem: neither has any vocal presence whatsoever. It could be chalked up to a sad attempt at broadening their fanbase or an unsuccessful yet passing effort in the name of experimentation (let’s hope it’s the latter), but it’s undoubtedly the most frustrating aspect of the record. There’s also little here that matches the searing intensity of “Island” from Leviathan (2004), but by no means is Blood Mountain sedated or toned down in any way.

Put simply, each song here (save the psychedelic closer “Pendulous Skin”) has at least one riff that absolutely slaughters most metal bands’ entire catalogs. Dailor has tightened up his kit work into something resembling a mechanized octopus; the maelstrom-like flailing that dominated past albums has been streamlined to lock into perfect time with each successive riff that the guitarists fire at him. For an example, feast on “Capillarian Crest,” which takes the average, say, King Crimson tune, injects it with amphetamines and steroids, grinds it to a pulp, then reassembles the remains with jaw-dropping levels of execution. Play this track for any metalhead and you’re guaranteed to get a frozen pause from the headbanging for the calm utterance of two words: “Jesus Christ.”

“Capillarian Crest” – Mastodon 4:25 (Blood Mountain, Reprise 2006)

“Siberian Divide” softens the texture slightly with some ringing acoustic guitars in 7/8, but is still dominated by thrash metal riffing and phenomenally complex drumming – my God, just listen to Dailor’s fill at 2:33. Cedric Bixler-Zavala from The Mars Volta drops in for some otherworldly operatic vocal shrieks, and at 4:14 the guitarists break into a demonically badass riff cribbed directly from the Slayer playbook.

“Siberian Divide” – Mastodon feat. Cedric Bixler-Zavala 5:32 (Blood Mountain, Reprise 2006)

Perhaps the best description of the lyrical content of “Siberian Divide” comes from Dailor, whose comments in an interview had me geekishly grinning from ear-to-ear:

“[The character is] caught in a blizzard where [he] becomes frostbitten and frozen and [he’s] starving and starts to hallucinate. [Then] this snow queen appears before him and tells him it’s okay to start eating his own flesh. And then he starts to do that. Then an aurora borealis appears, and he thinks it’s God, and it starts affecting this crystal skull he’s been toting up the mountain, and it starts to warm his body. That, coupled with the knowledge of the aurora borealis being God, gives him the strength to start to carry on again.”

And an army of prog-metal fanatics, looking up from their secret weekend Dungeons & Dragons tournament with handfuls of 20-sided die, nodded their collective heads in approval.