The Satanic Temple expects its second annual convention — held in Boston this weekend, and dedicated to Boston Mayor Michelle Wu — to be the largest gathering of Satanists ever.

The Satanic Temple, headquartered in Salem, is organizing the sold-out SatanCon at Marriott Copley Place April 28-30; it promises to bring a lineup of panels, entertainment, and a “Satanic Marketplace.”

“Really it’s just a normal conference, people are talking about issues that are close to people within the Satanic Temple,” co-founder and spokesperson Lucien Greaves told Boston Public Radio Wednesday.

Not to be confused with the Church of Satan, an earlier Satanic organization founded in the 1960s, the Satanic Temple is a non-theistic religious movement that uses Satanic imagery to actually promote the separation of church and state.

Their actions nationally include delivering reproductive health services in New Mexico and organizing after school Satan clubs. Locally, the organization is suing the city of Boston and Mayor Michelle Wu over her denial as a city councilor to allow the Satanic Temple to deliver the opening prayer customary before city council meetings.

But Greaves wanted to make clear, the Satanic Temple isn’t just a free speech organization, or a troll group.

“I think a lot of people make the mistake that our veneration of the character of Satan is an opportunistic ploy to poke fun of other religions and other such things, that’s not really the case,” he said.

So why use such a controversial figure as Satan, and why not just bill themselves as a straight free speech or civil liberties group?

“There’s a lot of different imagery depicted in Satan throughout the ages and a lot of that was brought forward by images meant to marginalize other people in an unjust way most often, and we kind of reclaimed that symbolism and reclaimed that character to stand up for the unjustly marginalized and the unjustly accused,” said Greaves. “For us, Satan is a literary metaphor that embraces these values we have of embracing our outsider status, and standing up against tyranny wherever we see it.”