The ceremony of blot starts with a blast. An ancient Moot Horn cuts through the congregation's idle chatter, allowing the clings of metallic pendants to rise and fill the new silence. The horn is a rallying call to all attendees—both in this realm and beyond. There is a period of meditation before fire-lighting and invocations, a time to considers ancestors, kin, future bloodlines. A runic mantra follows, linking congregants and immersing them in the energy of vibration. The ceremony closes with the passing of the Mead Horn, a curved drinking vessel filled with spirits. Everyone makes a toast, the horn is emptied, and the feast begins.

The ceremony of blot is carried out by followers of Odinism and Asatru, two denominations of the same religion focused on worshipping the Norse gods. There's Odin, the god of war, death, poetry, and the alphabet; Freyr, god of virility and fair weather; Freyja, goddess of love and fertility; and of course, Thor, the hammer-wielding god of thunder and lightning, as portrayed by Chris Hemsworth in the Marvel movies.

Together, Odinism and Asatru constitute the largest non-Christian religion in Iceland, officially recognized by Norway, Sweden, and Denmark. It's gaining steam in America, too, where Thor's Hammer is now allowed to be carved onto military gravestones and prisoners are granted special accommodations to carry out rituals.

But there's a dark side, too. "When I see the word Odinist, the red flags go off," says Joshua Rood, an expert on Old Norse Religion at the University of Iceland. "A lot of people who don't know any better, usually very new people, will consider themselves Odinists because they like Odin, they think he's cool. But they have no idea they're referring to themselves by a term that's connected to a movement that's racist."

The Swedish Asatru Society performs a ceremony. Photo via WikiMedia Commons

To understand Odinism—and the way that it became a religion entangled with racism, exclusion, and American prison culture—you need to start with the original Scandinavian pagans. These groups worshipped Norse gods through songs and ceremonies, celebrating the mythology of gods like Thor and Odin, who went by many names. Between the 8th and 12th centuries AD, Christians "explained" to the heathens about the One True God, and so-long went paganism, until the mid-1800s, when a nationalistic climate led Scandinavian countries to rediscover their own history. They found something to call their own—Norse Gods—and rebirthed the religion into Germanic neopaganism.

In 1936, Australian author Alexander Rud Mills established the First Anglecyn Church of Odin, which claimed Odinism as "the indigenous religion of the northern European people." In his opening liturgical text, he mentioned "the fall from grace of the White Race by being untrue to the spirit of their forefathers." Else Christensen, a Danish woman, was struck by the work. After WWII, Christensen and her husband Alex emigrated to Canada and founded the Odinist Study Group after WWII with the claim that "religion is in our genes." After Alex's death in 1971, she moved to the United States and published The Odinist newsletter.

The return to Norse gods was regaining steam. In 1972, Icelandic farmer Sveinbjörn Beinteinsson founded the Asatru Fellowship (or Ásatrúarfélagið)—a spinoff of Odinism—which was granted recognition as an official religion in Iceland. While many components are the same as Odinism—including the celebration of blot, the worshipping of Norse gods, the same Moot Horn blasts and Mead Horn gulps—the religion wasn't based on an indigenous claim. "The Asatru has a holistic, environmental touch—and they feel very closely connected to Mother Earth," said Michael Nielsen, a professor of Viking History at Copenhagen University, in an email. All are welcome, no matter your heritage or color.

But a few years later, in 1976, American Stephen McNallen also adopted the term "Asatru" for the creation of his own organization, the Asatru Folk Assembly, a non-profit organization based in Nevada City, California. (McNallen created a precursor to this organization in 1972, under the name The Viking Brotherhood.)

"I found the Norse system of courage, honor, and daring much more compelling than the submission and submergence of the individual I saw in Christianity," McNallen told me through email.

But rather than following the tree-hugging vibe of the Beinteinsson-created Asatru Fellowship, McNallen's American version adopted the Mills/Christensen "folk" style regarding the worship of Norse gods, the more "classic" version of Odinism. Generally speaking, in this in this context, "folk" actually means "racist" and has caused many opponents to suggest that he has co-opted the term and ideas of the Icelandic "Asatru" for his own hateful devices.

"[Odinists] claim they are opposed to racism, but they define racism very differently from the average person," says Rood. "They say, 'We're not racist. We just believe in keeping ethnicity separate.' Which... it's racist."

McNallen's point-of-view—which mirrors that of Odinist organizations both in America and Europe—is that everyone has their own culture, and we should stick to it. "I do not believe we are born tabula rasa, or 'blank slate,'" writes McNallen. "We are the latest edition of our ancestors in this slice of space and time. Our native culture, or a logical permutation of it, is the one that suits us best because it arises from our very soul." Despite the fact that McNallen's ancestors have been in America for 200 years, his bloodline was in Europe for 40,000 years before then, and thus, he argues, his ancestral line "transcends space, time, and mortality."

For his part, McNallen says he's "never claimed that non-Europeans cannot practice Asatru. But I wonder why they would want to follow European native religion rather than the entirely valid and worthy native religions of their own ancestors. I wonder what their own ancestors must feel at being slighted so."

So, while the European followers of Asatru worship Thor without the emphasis on racial or ethnic heritage, the Asatrus in America look more like Odinists, who emphasize racial heritage. It all gets kind of confusing. "I feel a bit sorry for both movements," writes Nielsen. "The sources about Old Norse religion were written down after centuries of Christianity, and it is therefore possible to fill in whatever suits you."

Related: VICE visits "The Wizard of the Saddle" in Memphis, Tennessee, the epitome of racism in America.

The idea has caught on in American prisons. The Holy Nation of Odin, Inc., a non-profit church that worships the Old Norse gods, is run by Casper Crowell from his prison cell in California's maximum-security Corcoran State Prison. Crowell is serving a 54-years-to-life sentence as a California Three Strikes offender, the final strike coming when he shot a man in Palm Springs in 1995.

To join Crowell'sHoly Nation of Odin, Inc., you have to pay $40 membership fees, unless you're incarcerated, in which case it's free. In order to be considered, you must give up drugs (prescriptions are OK), leave your political ideology at home, follow the sacred runes, keep holy the blot, and, oh yeah, be white:

This religion and way of life was indigenous to the peoples of Northern and Western Europe and so it remains so of their descendants today, "us"!

Crowell is a former member of the Aryan Brotherhood. He left because it wasn't as pure as he'd liked. Instead, he turned to the teachings of David Lane, the white nationalist founder of The Order who was serving a 190-year sentence for the 1984 murder of liberal radio host Alan Berg. Lane also infamously coined the term that particulary resonated with Crowell, the so-called Fourteen Words: "We must secure the existence of our people and a future for White Children."

It's not shocking, then, that followers of Odinism aren't known as being the most sterling of citizens. Glenn Cross, the 73-year-old who killed three people at Jewish institutions in Kansas last year, wears a Thor's Hammer medallion. Ryan Giroux, who killed one and wounded five in a shooting spree at an Arizona motel earlier this year, has Thor's Hammer tattooed on his chin. According to some reports, 15 percent of American Odinists are "overtly racist."

It's not so much that the white inmates believe in the religiosity of Odinism as much as they need to be affiliated with religious organizations to be granted certain rights behind bars.

"In jail, registering as Odinist has a different significance," writes Daniel Genis, ex-con-turned-journalist, in an email. "It's important because prisons are compartmentalized for reasons of security and religious callouts are often the only way to see someone from the other side of the joint."

Odin throws his spear at the Vanir host in an illustration by Lorenz Frølich (1895). Image via Wikimedia Commons

For all kinds of socioeconomic reasons, prison affiliations tend to fall along racial lines, and each of these groups have their own religious affiliations. Jamaicans and Caribbean-based gangs meet at Rastafarian gatherings. The Latin Kings are members of Santeria. Asians are Buddhist, Russians are Jews, Italians are Catholic. In 2003, the black nationalist group The Five Percenters brand-shifted to the moniker The Nation of Gods and Earths, which allowed African-Americans their own officially-sanctioned prison religion. White prisoners wanted the same type of thing. So, the white prison population took over the only religion they could call their own: "the original, indigenous faith of the English people."

"In theory, becoming an Odinist offers brotherhood, protection, and identity to a white prisoner who can find himself [in] crowds [dominated by] men of a different race," writes Genis. "As familiar as this may be to African Americans, it's new and terrifying to many white convicts."

It also grants the ability to symbolically fight the system: Following a 2005 Supreme Court ruling, Asatru/Odinists are allowed to wear Thor's Hammer pendants around their necks. "Prison offers few chances to express one's identity," writes Genis. "Men fight back with tattoos, which cannot be taken away and hairstyles. The only jewelry allowed are wedding bands and necklaces with religious insignia."

Which is why, every now and then, you'll hear a loud horn blast rattling the cold prison walls before the mead cup is passed, and why prisons are now, if not chock-full (there are no stats kept on inmate religions), then at least somewhat comprised of large, angry, heavily-tattooed white guys wearing necklaces that your precocious pre-teen Avengers fan may have on his Christmas list.