In three days, self-proclaimed "devil worshipers" will hold what's become a highly controversial black mass.
Those against the event are threatening lawsuits and creating petitions. One effort has even gone international.
Holding the black mass in the buckle of the Bible Belt is what event planners say they want, but it's what Christians are trying to stop.
"God has rights too, and when those rights are trampled upon with a black mass, which is a complete and open attack on God," John Ritchie, director of The American TFP, said.
An attack that Devil Worshipper Adam Daniels doesn't argue.
"Is it my duty as a vicar for the devil to spiritually attack his opponent? Yes," Adam Daniels with the Dakhma of Angra Maimyu said.
Now, the group that helped stop a black mass at Harvard in May is attempting to do the same in Oklahoma.
John Ritchie and his organization, The American TFP, created a petition that's collected 100,000 signatures worldwide and an estimated 115,000 on other petitions.
With each signature, an email is sent to the city.
"When a culture considers something like a black mass as a legitimate form of speech, then we're in dark days and dark times," Ritchie said.
In response, the city stands by its choice to allow the event but not the event itself. Adding, "Past attempts by the City to thwart an individual's free exercise of speech have resulted in costly legal battles which we have lost at taxpayers' expense."
Daniels interprets that as a clear path to exercise his First Amendment right.
"Every Sunday, they're in their pulpits blaspheming my god, and they have the right to do that, but I don't have the right to do the same in return," Daniels said.
"It's not right to use the First Amendment to be used as a club to beat Christians over the head," Ritchie said.
Daniels also said he wants to hold this ceremony in public to debunk myths portrayed by Hollywood.
The black mass has sold all 88 tickets.
The American TFP plans to come to Oklahoma and join hundreds of others in what they said will be a peaceful protest.