While there are variations in Christian theology about the nature of Satan and demons, traditional Christian thought holds that these creatures are evil, the threat from them is real and should be taken seriously. Exactly what self-proclaimed “satanists” think about all this is unclear, other than that they make a public show of worshiping Satan and calling upon demons for assistance.

Thus, it may be that the Oklahoma City satanists, who call themselves the Dakhma Angra Mainyu, believe that the black mass they’re holding on Sunday, Sept. 21, at the Oklahoma City Civic Center, is harmless fun, or a deliberate insult to Catholics (since the “black mass” is a perverted parody of the Catholic Mass), or even a serious attempt to call upon dark forces.

But according to the beliefs of a priest from the neighboring Diocese of Tulsa, both those putting on the event and those attending–although poorly attended in the past, this year’s event has sold out all 88 tickets–may be in spiritual peril.

Even though the event has been tamed a bit to comply with state law (the usually naked female “altar” will have lingerie; and vinegar is being substituted for urine) and it will no longer feature a Consecrated Host (after a legal challenge, organizer Adam Daniels returned his pilfered Communion wafer to the Church, specifically, Archbishop Coakley of Oklahoma City), Monsignor Patrick Brankin is worried.

Msgr. Brankin, the official exorcist for his diocese for the last four years, said to the Cathoic website Aleteia, “I am profoundly relieved that this group has returned to Archbishop Coakley the Consecrated Host which they intended to desecrate, but am still concerned that they have not backed away from all the other blasphemies and sacrileges involved in this ritual worship of Satan.”

As for the attendees, Brankin said, “I would think that there would be a real strong possibility, especially in the state of sin, that they would walk out possessed. They’re going into a situation where people are calling upon Satan to exercise dominion over everything in the state–dominion over people, places, our very land.

“They promise to do an exorcism of the Christians there, which, in their own foolish talk, involves puling out of the Holy Spirit. If someone went there out of curiosity, especially if there was a possibility that they were not in the state of grace, they could easily come out with a demonic attachment, whether it would be an oppression, obsession or a full possession.”

Another exorcist, speaking under the condition of anonymity to Aleteia, didn’t think that there is necessarily a rise in public black masses but believes there are plenty of them going on behind closed doors. However, when they do take place in public, he argues for the strategy employed by the Catholic Church in Boston, when another group of satanists planned to hold a black mass in a pub on the Harvard campus in May.

As previously reported by Breitbart News, Harvard itself dealt with the event (eventually moved off campus to a Chinese restaurant), while Catholics organized a Eucharistic Procession (in which a Consecrated Host is displayed and reverenced; click here for a set of pictures on Flickr) and then a packed prayer service at St. Paul Church, just off Harvard Square.

Said the anonymous exorcist: “The answer is to do what folks did in Boston. Catholics must organize Eucharistic processions and holy hours; they must fast and pray fervently for the cancellation of this event. We must petition our Lord, His Mother and all the angels and saints in this fierce battle against the powers of hell. To fail to fight this evil is to abandon souls to hell.”

The Archdiocese of Oklahoma City is taking that route, with a Eucharistic Holy Hour, an outdoor Eucharistic procession and a Benediction service from 3-5 p.m. local time at St. Francis of Assisi Church (named for the patron of current Pope Francis). Click here for details on the event, to which Archbishop Coakley has already invited Catholics from outside of Oklahoma, especially those in neighboring Texas.

Over 88,000 people have signed an online petition to stop the black mass, but city officials have repeatedly said they have no legal right to do so, provided the organizers have paid the requisite fees and stay within local laws.

But even if the black mass is perfectly legal, Archbishop Coakley fears for his flock and for the people involved.

In a statement posted on the Archdiocese Website, he said: “Even though our city leaders apparently do not take this threat seriously, I do. As a Catholic priest and bishop, I have witnessed in my ministry the battle between forces of good and evil, in both ordinary and extraordinary ways. It is not merely a struggle rooted in human weakness and ignorance, though these are certainly the source of much suffering and mayhem in our lives and in our world. Demonic activity and the chaotic forces of evil are very real. The madness of war, accompanied by increasingly brutal acts of terror, the violence in our schools and communities are all evidence that something is terribly wrong.

“The crucial battleground for the forces of good and evil is the human heart. As a Christian, I believe that Jesus Christ came to conquer the power of sin and to cast out demons. This was an essential part of His mission and ministry. It continues in His Church.”

After calling for “all Catholics as well as other Christians and people of good will” to come to St. Francis of Assisi on Sunday, Archbishop Coakley concluded with: “Finally, let us demonstrate our faith in the power of the Lord’s grace by praying for the conversion of those who are perpetrating this sacrilege and are bound by the Evil One. ‘But I say to you, love your enemies, and pray for those who persecute you, that you may be children of your heavenly Father, for He makes His sun to rise on the bad and the good, and causes rain to fall on the just and the unjust’ (Mt 5:44,45).”