Pop music review: High on Fire, Converge, Mastodon and Dethklok

It’s telling that the most orthodox act on one of the season’s most anticipated metal package tours was the one composed of cartoon characters. The sprawling quadruple bill of High on Fire, Converge, Mastodon and Dethklok -- the last a Gorillaz-like animated band project for self-aware Hessians -- proved Thursday night at the Hollywood Palladium that while the heaviest strains of rock music are very much thriving, the rule book for what constitutes metal today has been burned at the stake.

Booked at the distinctly un-metal hour of 6:30 p.m., High on Fire’s druggy, swaggering and dread-laden metal had to compete with the brutal reality of playing a dinner-time set prefacing a very long night of difficult music. No matter the strength of their bleak grooves and tooth-cracking clatter -- and they’re strong indeed -- that’s a tall order.

The wonkish post-hardcore act Converge had a slightly easier time of it. The Massachusetts-based band was one of the early adopters of the metalcore genre, in which the speed and ferocity of ‘80s American punk gets applied to the precision-cut riffs and polyrhythms of thrash. Converge’s new album, “Axe to Fall,” expertly refuses to put more than one foot in any camp of heavy music -- guitarist Kurt Ballou is equally at home squealing off pinch harmonics in a throwback solo or a sub-sonic churn of contemporary white noise. At times the restless pummel of drums even leans toward something Sun Ra could nod to.

Speaking of deep-space exploration freaks, the Atlanta band Mastodon has become a bit of a Lil Wayne figure for modern metal -- an inventive, genre-beloved act that has crossed over into hipper media favor and much wider sales even as longtime fans wonder what exactly they’re up to anymore.

Fortunately, in Mastodon’s case, the band made a landmark album this year, the daffy yet uncannily haunting and ambitious “Crack the Skye.” Tracks from “Skye” grind a bit slower and have more breathing room than older efforts “Leviathan” and “Remission,” and snatches of ambient synthesizer and delicately arranged vocal harmonies added an unexpected resonance to the music.

Mastodon is one of the few bands in metal that can have enormous choruses without being remotely pop-inclined, and that made for some unexpectedly powerful climaxes on cuts like “Crack the Skye.” They still made time for old-fashioned cackling and bludgeoning on “Oblivion,” but the set cemented Mastodon as one of the most restless bands in heavy music.

Dethklok, however, is simultaneously both a loogie in the eye of the self-serious corpse paint set and an adoring love letter to the inherent absurdity of the rock-god psyche. In the Adult Swim comedy “Metalocalypse,” Dethklok is the world’s 12-largest economy, a favored target of a shadow government spy team and routinely responsible for fans killing themselves with adoration for singer Nathan Explosion, yet they’re barely functional as human beings. The show is the best deadpan sendup of a genre since “Fear of a Black Hat,” but the best parody always comes from love, and that’s certainly the case here.

The live incarnation of Dethklok -- helmed by show creator and singer-guitarist Brendon Small -- would be a considerable force in metal in its own right. Beneath a show-length animated sequence plotted vaguely around a military conspiracy to render Dethklok fans unable to spend money on Dethklok merchandise (thus destroying them), Small growled and wailed with a serious technical precision. The performance was laden with genre in-jokes returned by the sold-out crowd; they knew good and well they were being ribbed.

In a way, Dethklok was too perfect on paper to not become a real band. But the group’s existence also underlines how real bands in today’s metal scene rarely come with scripts anymore.

august.brown@latimes.com