To the great consternation of the Church, over the past 17 years veneration of a Mexican folk saint that personifies death has become the fastest-growing new religious movement in the West. At this point there are no systematic surveys of the precise number of Santa Muerte devotees, but based on 10 years of research in Mexico and the US, we estimate there are some 10 to 12 million followers, with a large majority in Mexico and a significant presence in the United States and Central America. However, the skeletal folk saint, whose name translates into English as both Saint Death and Holy Death, now has followers across the globe, including in the UK, where there are sufficient devotees to support a Facebook group specifically for British followers.

As the name would indicate, Santa Muerte is a Mexican folk saint who personifies death. Whether as a plaster statue, votive candle, gold medallion or prayer card, she is most often depicted as a female Grim Reaper, wielding the same scythe and wearing a shroud similar to that of her male counterpart. She is also frequently shown with an owl, which in Mesoamerican traditions symbolises death.

Unlike official saints, who have been canonised by the Catholic Church, folk saints are spirits of the dead considered holy by the local populace for their miracle-working powers. In Mexico and Latin America such folk saints as Niño Fidencio, Jesus Malverde, Maximon and San La Muerte (the Argentine counterpart of Santa Muerte) command widespread devotion and are often invoked more than the official saints. These folk saints are united to their devotees by nationality, cultural affinities, locality and social class. A Mexico City street vendor explained the appeal of Santa Muerte to us by saying: “She understands us because she is a battleaxe like us.”

Where the Bony Lady, one of Santa Muerte’s many monikers, differs from other folk saints is that for most devotees she is the personification of death itself and not of a deceased human being. She is popular among cultural Catholics who don’t know, or care, that she is condemned by the Church.

When Pope Francis visited Mexico for the first time in 2016, he rebuked the object of the fastest-growing new religious devotion in the Americas on his first full day in the country, thus ensuring that Catholics were aware of the Church’s stance. During a scathing castigation of his fellow bishops, the first New World pope disparaged Santa Muerte as a dangerous symbol of narco-culture:

“I am particularly concerned about those many persons who, seduced by the empty power of the world, praise illusions and embrace their macabre symbols to commercialise death in exchange for money, which, in the end, “moth and rust consume” and “thieves break in and steal” (Mt 6:19). I urge you not to underestimate the moral and antisocial challenge which the drug trade represents for Mexican society as a whole, as well as for the Church.”

“Praise illusions and embrace their macabre symbols to commercialise death” is an obvious reference to the saint of death, who had already been condemned by name by Cardinal Gianfranco Ravasi, president of the Pontifical Council for Culture, during a four-day visit to Mexico in 2013.

That both the Pope and a high-ranking Vatican official have condemned veneration of a folk saint who has only become known to 99 per cent of Mexicans over the past 17 years – when the first public shrine to Santa Muerte was erected in Mexico City – is most extraordinary. Latin America is home to scores of other folk saints that aren’t recognised by the Church, yet only Mexican Santa Muerte has been singled out for censure. More recently, in March this year, Archbishop John Wester of Santa Fe, New Mexico, also denounced the cult. He said that those worshipping “Saint Death” won’t find the answers they’re looking for and warned them that veneration of Santa Muerte is not consistent with Catholic teaching.

There are three major reasons for these condemnations of Santa Muerte. First, as the fastest-growing new religious devotion from Canada to Chile, the death saint presents stiff competition to a Church that has been in sharp decline in Latin America since the 1970s – and is now haemorrhaging members in the US, where the Catholic percentage of the population dropped from 24 to 21 per cent between 2007 and 2014. Already in a state of panic over burgeoning Pentecostalism, the Church in Mexico and Central America now has to contend with a heretical folk saint which mostly claims devotees who still consider themselves Catholic, especially in Mexico where some 75 per cent of Santa Muertistas reside.

Second, the Church views veneration of the Bony Lady as tantamount to Satanism since death is the antithesis of the eternal life that Jesus Christ made possible for believers through his sacrifice on the Cross. Moreover, Catholic saints were real human beings who were canonised for being paragons of holiness. Since death isn’t a human being, it can’t possibly be a saint – unlike St Jude Thaddeus, the wildly popular patron of lost causes who, because of competition with Santa Muerte in Mexico, is now the only Catholic saint among thousands that has a monthly feast day, on the 28th day of each month.

Finally, the first Jesuit pope specifically criticised the skeleton saint as a “macabre symbol” of narcos who have sent tens of thousands of their compatriots to an early grave over the past decade. Though he doesn’t receive much media coverage for it, Pope Francis is a major anti-drug crusader who has warned his fellow Argentines to avoid the “Mexicanisation” of the country. At the behest of the Mexican Church, former president Felipe Calderón pointed to Santa Muerte as religious enemy number one in his war against some of the drug cartels.

In order to understand the mushrooming popularity of Santa Muerte, who was practically unheard of a decade ago and is now the most venerated folk saint in the Americas, it is essential to understand her appeal to certain segments of society in Mexico, and indeed across the continent.

Santa Muerte is known for her followers among drug dealers, but additionally among the disenfranchised: those who have been marginalised by mainstream society or who purposely inhabit the peripheries. Her followers include the impoverished, criminals, sex workers, prisoners and members of the gay and transgender communities. The destitute generally live in dangerous neighbourhoods where death is part of everyday life. The desire to worship death for this populace stems in large part from the need to accept death, in order to place a familiar face on and not be fearful when confronted with what many dread.

The poverty-stricken also pray to the skeleton saint for a holy death (one of her English translations); namely a natural end, as opposed to one caused by criminal brutality. They believe it will be easier to traverse purgatory and get to heaven if their soul is not tormented by violence.

Many devotees have grown up in Catholic households and identify as Catholic, but either due to the nature of their profession or their sexual orientation they acknowledge that they are not ideal members of the Catholic Church, and that God might judge them for the sins they have committed. Death, however, as personified by Santa Muerte, does not judge, according to her followers. Whether one is rich or poor, gay or straight, a recidivist or a law-abiding citizen, death comes to us all. Therefore, devotees believe that Saint Death listens to everyone’s prayers no matter who they are. The marginalised furthermore relate to the folk saint due to her ostracism by the authorities.

Those in dubious professions, such as drug dealers, also believe they can turn to Santa Muerte for their petitions and that she will listen, unlike God who would not condone their actions. If for example, narco-traffickers wish to get their methamphetamine shipment safely across the border, or ask for protection from law enforcement officers keen to bust them or rival cartels seeking to eliminate them, they typically invoke the skeleton saint. They might pray to her while lighting a black votive candle, which is the colour used by devotees for pernicious petitions.

Often supplications take the form of a quid pro quo where devotees implore the folk saint for a favour in return for a gift they will grant her if their prayers are heard. Some devotees get tattoos of her imagery as an oblation. Others thank her with tequila, cigars, cigarettes, chocolate or flowers, which are believed to be her favourite offerings.

Such devotional activities furnish criminals with the impression of controlling supernatural forces with which to protect themselves and seek vengeance in a world characterised by brutality and uncertainty.

To understand the devotion to death, we must also examine the historical record. Across the Americas, and in particular in Mexico, death deities were prevalent during the pre-Hispanic era prior to colonisation. Many indigenous peoples, such as the Maya and the Aztecs, turned to death gods and goddesses for healing ailments, and also to guarantee safe passage into the underworld.

When the Spanish arrived in the New World, their missionaries brought with them many effigies to aid with conversion to Catholicism, including the Grim Reaper. In Spanish iconography, this representation of death was depicted as a female figure, or Grim Reapress, known as La Parca. As local cultures venerated death deities, it is likely that the female skeletal image was reinterpreted by native peoples as a figure akin to a goddess of death, thereby transmogrifying the Grim Reapress into a heretical hybrid death saint that contained both indigenous and Catholic elements.

Historical records of the Spanish Inquisition mention Santa Muerte twice in the 1790s. Inquisitors discovered and destroyed two shrines to her in central Mexico. Following that, the skeleton saint faded from the records until the 1940s when it was discovered that women were turning to her for love petitions. But with the recent grim advent of the drug war, she has returned in full force.

Many wonder whether the emergence of Santa Muerte is connected to the Mexican Day of the Dead, in which families erect private altars honouring deceased loved ones and offer gifts of sugar skulls. There is no direct connection, though both are part of the larger death culture that pervades Mexican culture and history. However, November 2, All Souls’ Day, has become the unofficial feast day for Santa Muerte and in the last weeks of October the Church issues warnings to parishioners to leave Santa Muerte out of their Day of the Dead commemorations.

According to Fr Gary Thomas, a Vatican-trained exorcist for the Diocese of San José in California, devotion to Santa Muerte comes at a cost. Fr Thomas told the Catholic News Agency in 2016 that he had prayed with people who had suffered from satanic struggles after supplicating Santa Muerte. “I have had a number of people who have come to me as users of this practice and found themselves tied to a demon or demonic tribe,” he said.

Fr Andres Gutierrez, the pastor of St Helen parish in Rio Hondo, Texas, explained in 2016 that those most at risk are cultural Catholics who are unaware of the Church’s warnings about the devotion, but could potentially open the door to demonic forces by engaging in it. For clergy such as Fr Ryan Kaup, a Nebraska priest active in a Hispanic ministry, veneration of a fictitious folk saint who does not represent a real person is a perversion of faith.

However, although those who regularly attend Catholic churches and follow papal pronouncements might be dissuaded from devotion to Santa Muerte, those at the margins of society who face danger and death daily, or whose lifestyle choices jar with those extolled by the Church, may not be persuaded to, or be able to, abandon either their way of life or their faith in the folk saint.

Dr Kate Kingsbury is an adjunct professor at the University of Alberta. Dr Andrew Chesnut is Bishop Walter F Sullivan Chair in Catholic Studies and Professor of Religious Studies at Virginia Commonwealth University and author of Devoted to Death: Santa Muerte, the Skeleton Saint (Oxford University Press)