This is the sixth of Hèctor Parra’s stageworks, but only the second by the Spanish composer to be issued commercially on disc. His earlier “Hypermusic Prologue“ from 2009 was a mind-numbingly complicated sonic experience—one of those conceptually overblown music-theater experiments that every “serious” European composer of the past decades has felt impelled to foist on audiences.

But in the ten years since, Parra shed the pretentiously “progressive” schtick in favor of a more direct operatic language. His 2019 “Les Bienveillantes,” recorded live by b•records at its Ghent premiere, may as well be by a different composer. It’s overwhelming for the right reasons—an intense, three-hour behemoth that is almost too effective in its ability to probe the maggot-ridden recesses of the human heart. This is a work that leaves one feeling emotionally disemboweled.

Händl Klaus’ libretto—mostly in German, with portions in French—is based on a 2006 novel by Jonathan Littell. The title, translated in the book’s English edition as “The Kindly Ones,” is a reference to the third of Aeschylus’ “Oresteia” plays. Orestes is pursued by the mythical Furies, monstrous goddesses who torture him for his act of matricide. When the Furies reluctantly agree to grant him pardon, Athena bestows on them the name Eumenides, meaning “gracious ones.”

“Les Bienveillantes” is a retelling of the “Oresteia” set during the Second World War. Orestes is recast as an SS officer, Max Aue, who’s coerced into service after he’s caught cruising for men in a Berlin park. At first, we’re inclined to sympathize with his self-contradictory identity as a queer Nazi, even as we witness him participate in the most brutal episodes of the conflict: the Babi Yar massacre, the siege of Stalingrad, and Auschwitz.

But over the course of the sprawling narrative, layers of psychological tissue are slowly peeled back, and we learn who Max really is. When he visits his mother and stepfather in France, the couple confronts him about an incestuous affair he carried on with his sister, Una. That night, Max hacks them to death with an ax. He’s trailed for the remainder of the plot by a pair of detectives who stand in for Aeschylus’ Eumenides.

In an oft-quoted essay from 1962, social critic Theodor Adorno argued that it was impossible to represent an incomprehensible tragedy like the Holocaust through conventional artistic channels. For Adorno, a more confrontational musical idiom allowed modernist composers like Schoenberg to address the war with greater immediacy and authenticity: “The uncompromising radicalism of their works…endows them with a frightening power that impotent poems about the victims lack.”

Parra has diverted from this tendency toward alienation. On the contrary, his score is steeped in seductive beauty. Max’s opening monologue introduces a nocturnal texture that reappears throughout the score in various guises: a phantasmagorical swirl of sweeping harp, twinkling celesta, and sinuous English horn, all enveloped in a perfume of shimmering strings. Peter Rundel coaxes such intoxicating sonorities from the Symphonic Orchestra of Opera Ballet Vlaanderen that we’re apt to miss what exactly Max is singing.

Backed by this dreamy haze, he tenderly intones the paraphrased tune of a German lullaby. Only, its nursery-rhyme text has been replaced so that it now describes the dreadful division of labor that made the Holocaust possible by diffusing responsibility: “someone shows you a room / someone closes the iron door / someone’s hand opens the tap.” A sense of disgust sets in once we realize how easily we’ve been manipulated. How could we find aesthetic pleasure in these heinous words?

In many ways, Max stands as an allegorical representation of the German people’s paradoxical nature: simultaneous purveyors of High Culture and wreakers of genocidal destruction. We’re impressed by his refinement, his sensitivity, and his appreciation for music—he’s an ardent admirer of Bach, that quintessential deutscher Meister. We couldn’t imagine that he’d possess the capacity for evil. So the bloody slaughter of his mother and step-father, who stand in for Aeschylus’ Clytemnestra and Aegisthus, feels wildly out of character.

We’re willing to make excuses for Max. We assume that, like Orest, he was simply exacting his rightful revenge—even if it isn’t quite clear why they deserved it. And anyway, the murder wasn’t committed consciously, but carried out in a sleepwalking stupor. The passage where Max surveys the carnage the following morning is accompanied by a piano sarabande reminiscent of the one from French Suite no. 5. It’s a mostly convincing pastiche of Bach, but it’s marred by strange intervals that lend an uncanny quality, hinting at something unspeakably sinister.

Indeed, the opera’s sound world is steeped in decadence, conjuring an atmosphere of orgiastic excess and moral rot. Richard Strauss comes to mind. Obviously the plot is drawn from the identical mythic source as “Elektra.” Parra’s score often evokes the sonic sadomasochism that reigns in Strauss’ House of Atreus, with all its pricking, whipping, and slapping effects.

But the sickening sensuality and putrefying prurience of “Les Bienveillantes” is more redolent of “Salome.” Max’s incestuous obsession culminates in a scene far more disturbing than the Judean princess’ necrophilic kiss. Left alone in his sister’s home, he dons one of her dresses and performs what can only be described as an act of architectural copulation, making love to house’s furniture and décor. A moaning half-step motive—equal parts coital and queasy—drives this perverted Liebestod, which builds like a frenzied fever dream toward a terrifying climax.

This is the kind of opera that scholars of the future will analyze and unpack in multi-volume monographs. But in some ways, it feels as if Parra was too self-consciously intent on producing a work that would rank alongside the great “war operas” (his phrase) of the 20th century. Berg’s “Wozzeck” and Zimmermann’s “Die Soldaten” are quoted liberally, as is Shostakovich’s “Babi Yar” Symphony. And as in “Wozzeck,” Parra incorporates instrumental forms into the dramatic structure of each scene. “Les Bienveillantes” is conceived as a baroque dance suite in seven movements. Though, this is how Littell organized the original novel, giving the chapters titles like “Allemande” and “Gigue” to reflect Max’s love of early keyboard music.

In their mission to construct something monumental, the creators may have overcompensated in places.

Klaus’ libretto could do with some ample trimming—it’s possible to tell the same story just as effectively in an hour less. Max’s monologues, in particular, tend to ramble on redundantly. And there are superfluous characters and episodes that serve little function. The most effective scene is, in fact, the briefest and least cluttered. Klaus wisely chose not to attempt a literal depiction of Auschwitz; instead, he encapsulates its horrors in a poem about ants carrying bits of human remains out of an oven.

Parra sets these disquieting verses as a “Menuet (en rondeaux)” for Max’s sister, Una. Soprano Rachel traces the number’s angular phrases with crystalline precision. Her tone is impeccable, but eerily dispassionate, establishing a mood of icy distance. This renders the orchestra’s recurring “rondeau” subject all the more shocking—not at all like a refined courtly dance, but rather a pounding juggernaut of a theme that only happens to be in a minuet meter.

As Max, tenor Peter Tantsits rises to superhuman feats to take on what is no doubt one of the most physically, intellectually, and vocally demanding roles written this century. His performance is a master class in characterization. In the initial scenes, Tantsits’ unaffected lyricism conveys a naïve young man genuinely distressed by the war crimes he’s forced to carry out. And there’s something almost touching about his childlike inflection during Max’s post-murder speech—standing over his dead mother’s body, he repeats the word maman with sweetly innocent simplicity.

In the second half of the opera, Tantsits vocally charts his character’s breakdown. His delivery becomes desperate and unhinged, verging on sobbing and screaming. In a bizarre unaccompanied passage, he relates Max’s tall tale about accepting a medal from Hitler and biting the Führer on the nose. The tenor’s giddy giggles, cartoonish falsetto, and sarcastic outbursts makes it clear that we’ve been dealing with an unreliable narrator spiraling into madness.

As Max’s mother, Natascha Petrinsky’s tessitura is set intentionally too high so that the mezzo consistently sounds like she’s shrieking. It’s as if we’re hearing her filtered through Max’s twisted mind—an innocent woman transformed into a shrill harpy in order to justify his homicide. Tenor Gianluca Zampieri plays the flatulent Dr. Mandelbrod as a grotesque clown, channeling Gerhard Stolze’s legendary portrayal of the Captain from “Wozzeck” (whose leitmotif makes an appearance). Tenor Michael J. Scott and bass-baritone Donald Thomson add some comic relief as the bumbling yet persistent detectives; with their back-and-forth banter and exaggerated vocal contrast, they come off like a Laurel and Hardy vaudeville duo. Hanne Roos, Maria Fiselier, Denzil Delaere, and Kris Belligh embody a kind of Greek chorus, commenting on the action and providing madrigalian descriptions of some of the opera’s ghastlier imagery.