When Opeth released Heritage in 2011 -- the wonderfully indulgent, somewhat unfocused exercise in prog rock aesthetics -- some longstanding fans were offended because the band had abandoned death metal.

Truthfully, they had been exploring prog in fits and starts since 2005's Ghost Reveries.

Pale Communion completes the transition, proving that Heritage was not only a next step, but a new beginning altogether.

Vocalist, songwriter, and guitarist Mikael Åkerfeldt has obviously been listening to loads of prog in the interim -- ELP's debut, Deep Purple's In Rock, early King Crimson and Eloy, National Health, U.K., Bill Bruford's early solo work, Pär Lindh, and even jazz fusion.

Produced by the singer and mixed by Steven Wilson, Pale Communion states its ambitions outright.

Opener "Eternal Rains Will Come" explodes with knotty, labyrinthine organ (from new keyboardist Joakim Svalberg) and Martin Axenrot's skittering, propulsive drums.

Åkerfeldt's and Fredrik Åkesson's serpentine yet raucous guitars and Martín Méndez's fat, humming bassline kick in immediately thereafter.

They all stop on a dime to be replaced by flute and acoustic piano.

After another few moments, they return to establish the song's vamp and melody.

Åkerfeldt's multi-tracked vocals don't enter until three minutes in, then give way to a dazzling finish provided by a guitar solo and massive swathes of organ and Mellotron.

Lead single "Cusp of Eternity" employs repetitive metal guitar and bass riffs, while the modal melody suggests Middle Eastern origins.

"Moon Above, Sun Below" is the set's hinge piece and longest track.

It contains no less than five sections in nearly 11 minutes.

These are introduced variously by samples of Tibetan thigh-bone trumpet and vibraphones, as well as acoustic guitars, Rhodes piano, thundering organ, anthemic electric guitars atop cracking rim shots, kick drum, and a forceful bassline that creates dynamic textural passages illustrating the rage, loss, and acceptance in Åkerfeldt's lyrics.

"Goblin" is an instrumental, a tightrope walk between hard rock and jazz fusion, and it's among the finest things here.

This is countered by "River," with rich, multi-layered vocal harmonies, 12-string, piano, glistening cymbal, and snare, highlighted by a melodic electric guitar solo à la Argus-era Wishbone Ash.

The metallic syncopation in "Voice of Treason" is dramatic with Eastern interludes via the primary instruments, painted by Mellotron as Åkerfeldt soars.

The first half of closer "Faith in Others" is instrumentally sparse; it begins reaching for the skies about halfway through, but gets dialed back to allow the gorgeous melody prominence.

Pale Communion is more focused and refined than Heritage.

Though they readily display numerous musical influences here, ultimately Opeth sound like no one but themselves.

This set is a massive leap forward, not only in terms of style but also in its instrumental and performance acumen; it is nearly unlimited in its creativity.