Two years after resurrecting their more aggressive tendencies via 2002's suitably named Genesis album, Greece's Rotting Christ forged into realms unknown once again with their eighth studio album, the semi-conceptual Sanctus Diavolos.

And while previous Rotting Christ efforts had insinuated a ceremonial occasion, Sanctus Diavolos felt like an outright ritual, an intricate black mass marked by lush, orchestrated layers of sound stacked into each and every song.

Initial offerings come fast and furious, starting with the decapitating intensity of "Visions of a Blind Order," the "Carmina Burana"-recalling choruses of "Thy Wings Thy Thorns Thy Sin," and the petrifying marshal display of "Athanati Este" -- all of which find vocalist Sakis waging battle with massed choirs of the damned and abusing electronic samples like never before.

Yet, despite all of these sonic accoutrements, Sanctus Diavolos is Rotting Christ's first release since a return to their original bare-bones trio formation, making it evident that no small amount of studio trickery (welcome as it is, given the results) was employed in its creation -- not least of which being the surprising improvements in the rhythmic department, where complex tracks like those cited above and the particularly awesome "Tyrannical" would suggest that the normally technically impaired Themis was either replaced by a drum machine, or miraculously learned to play like a machine.

Whatever the case may be, it's hardly his fault alone when Sanctus Diavolos falters on the severely atonal "You My Cross," the oppressive "Shades of Evil," and the sometimes plodding "Doctrine," only to rebound in spades thanks to positively sublime, surprisingly musical passages present in the faux-Gregorian chants of "Sanctimonious"; the furious, densely layered (and nearly danceable!) "Serve in Heaven"; and the mesmerizing invocation made by the all-encompassing title track.

All in all, Sanctus Diavolos isn't perfect, but it may be Rotting Christ's most mature and sophisticated release to date, while proving consistently engaging throughout.