At the end of Diamanda Galás’s generous and delicious encore to her spell-binding Halloween show, she sang “Pardon Me, I’ve Got Someone to Kill” and “Gloomy Sunday.” A man in the row behind me wept loudly.

The effect of music differs with each listener, but the cause, the music making, is in each case the same. And Galás has been reaching deep into listeners’ beings with her voice for decades—she changes things, moods, perspectives, values.

Galás’s history and image are a costume she wears over her musicianship, which in a way was expressed by the elegant, black Victorian gown she wore. With her upswept raven hair, her white china makeup that emphasized her long, sharp cheekbones, and the parlor-like stage dressing, her presentation was of a 19th-century parlor performer. She could either have been a ghost, returning on Halloween night to briefly communicate with us, or else we were somehow looking back through a crack in the space-time continuum to a tableau-vivant from over a hundred years ago.

Presentation has always been essential to Galás as a dramatic device, whether drenched in blood for her Plague Mass or topless when singing Defixiones: Will and Testament, . What’s on the surface—the costuming, the song titles—means she has always been misapprehended, even by her fans. The Litanies of Satan and Masque of the Red Death have had many characterizing her as Satanic (for good or ill), and her look places her in the goth lifestyle.

These are parts, but she is none of these. She is an atheist who makes liturgies about God, Satan, and the judgment of the afterlife. She mourns, like in Vena Cava, not with sentimentality but with viciousness. She is only and always, like the title of one of her albums, a singer.

The things she can do with her voice, its range and fullness, her breath support and vibrato, lead critics to call her “operatic,” and she has made plenty of new music that has that kind of drama—but at her core Galás is a blues singer, one of the great ones.

Yes, she sings the blues that we know, the twelve-bar, I-IV-V progressions about poverty, sex, and death. But there’s the blues, then there’s the Blues—the global, eternal human experience of hardship, pain, suffering, brief moments of joy. Every musical culture has the Blues, and it’s been around since man first became musical.

The Blues comes out of the soil, and it’s in our DNA—the same stuff as that of ancient peoples who worshipped even more ancient, strange gods. It’s bound tightly in our lizard brains. Galás sings from there, and that’s where she touches us, at a distance, with her voice. Evaluating her recordings and most specially her performances is pro forma and irrelevant. She sings the hell out of everything, and it doesn’t matter whether that’s good or bad, because either you crave the experience she gives you, or you fear it.

And so she came on stage at Murmrr—a striking old synagogue that was also clearly once a movie theater—looking both ethereal and monolithic, an all-powerful ancient goddess with a benevolent demeanor. She sat at the piano and played and sang songs from her two great new albums, All The Way and At Saint Thomas the Apostle Harlem (she is an excellent pianist, mixing blues, rock, classical romanticism, and improvisation. Her fingers on the keys are powerful, smooth, or abrading, depending on her ideas.).

Now in her early sixties, her voice seems like it will last beyond the expiration of her body. Age has added weight in every dimension, pushing the borders of her sound and rounding it out, making it more substantial than ever. It’s still as clear as deep, still water, and it is still astonishing to hear her go from broken glass vocalizations in the back of her throat to full sustained notes in her enormous tessitura that shine like black pearls.

Inside that voice on Halloween were the ancient spirits of the soul, the hauntings of racial memories. She sang “O Death” as a tribute to death itself, pushing the edge of that feeling, and with her presence on stage she sounded like she indeed was death, relishing her own stature and power. It was spine-tingling and comforting.

What Galás did, what she always does, is pass judgment. In our current culture, that is both what we constantly want to do and supposedly the worst thing you can do to anyone. It is absolutely not done in popular music, which has to hew politely to the formulas of each genre, and is compelled by the market not to offend. Even music that stands against or outside general culture, like metal or hip hop, regresses to its own mean.

In a country that is so rude, crude, cruel, and savage, it is fake in the worst way: it pretends things are better than they are, or that they’ll get better. For most of us, they won’t. We are all savages after all.

Galás is the high priestess of our savagery. She sings songs about love and death in a way that shows what they really are: songs about fucking and killing. This passes judgment on our social and political bullshit—our façade of civilization; then at the end it offers a benediction that fucking and killing are human, and we’re only human, after all. This is not the kind of thing discussed in polite company, whether it’s PBS or Mitt Romney’s “quiet rooms.”

Galás is not polite. But she’s not mean. She excoriates the savage falseness of this country by making our baseness beautiful. She is Shiva, creator and transformer of worlds.