A Satanist Veterans Affairs staffer filed a civil rights complaint over their supervisor’s joke sign reading, “Not today, Satan, not today” — claiming it was a “grotesque Christian supremacist” symbol.

The unidentified Air Force veteran — who “subscribes to many non-theist teachings (including Satanist)” — had the case taken up by the Military Religious Freedom Foundation, whose founder agreed to file a formal complaint.

The self-described Satanist complained of an already hostile work environment at the undisclosed facility when they were invited to their supervisor’s office — and saw what they deemed to be a “grotesque Christian supremacist” sign.

It was placed “in such a way that it was physically directed at anyone sitting in the guest chair across from her desk,” the offended staffer wrote in an email to the civil rights group.

The employee then sent a “passionate and deeply emotional email to my supervisor describing my feelings towards her and it.”

The civil rights group’s founder and president, attorney Michael Weinstein, agreed to represent the employee and prepare to file a lawsuit.

He agreed because the sign was a “noxious example of trying to express a particular religious view in a situation where it simply was not warranted,” Weinstein told the Christian Post.

He was also scheduled to meet with the offending supervisor, the Satanist veteran and a union representative, but before the meeting took place, the supervisor’s higher-up had already met with the employee’s supervisor and had ordered her to take down the sign, Weinstein told The Post.

Upper management is now also considering “bringing in more cultural sensitivity awareness training, moving me to a new supervisor and sending an apology email to my entire team,” the Satanist vet said in a thank you email to the group.

Weinstein has since defended the civil rights group’s actions.

When questioned by the religious news outlet about how he responds to critics who claim he is defending devil worship, the attorney said some people are simply ignorant about “the full nature of Satanism.

“It’s not sacrificing children at midnight with knives,” he said, though he acknowledged that most people consider Satan evil.

He went on to describe the fight to get the sign removed as a fight for religious freedom.

“Our republic is meant to be a secular democratic republic; that’s how we do it in this country,” he said.

“We don’t look at whether Satan is bad, or Jesus is bad, or Vishnu is bad, or Buddha or Yahweh. We look at the time, place and manner of an expression of a faith or non-faith tradition.”

“I ask people all the time [to] remember, we’re not a Christian nation, we’re not a Jewish nation, we’re not an Islamic nation. We’re a secular democratic republic.

“And that’s why we have a separation of church and state,” Weinstein said. “It’s all time, place and manner.”