Rose City Comic Con hosted hundreds of cosplayers earlier this month, who came dressed as everything from R2D2 to Link from The Adventures of Zelda.

But it turns out there was also an alarming number of Nazi costumes, including costumes based off Red Skull, Hydra and Nazi HelloKitty.

Nazi cosplay isn't new, and neither is Rose City Comic Con's policy against what it refers to as "hateful symbols." This year, however, Rose City Comic Con founder Ron Brister made an important clarification to the policy: Nazi costumes are "100 percent banned, all the time."

As first reported by Bleeding Cool, Rose City Comic Con released an updated costume policy on Thursday, banning all Nazi-related costumes.

Hateful symbols aren’t welcome at Rose City Comic Con. Historical costumes can be great, but reminders of unspeakable atrocities are not appropriate – this goes for Old School Hydra and Red Skull or any other Nazis from entertainment properties. Those figures, while comic-related, are still very much Nazis. As a result, they are 100% banned, always. This includes any sort of “ironic” or satirical costumes that re-appropriate Nazi paraphernalia or gear. You won’t just be banned from that year’s convention. You will be banned from coming to RCCC for life.

Brister says he wanted to change the policy after receiving complaints from several people on social media, during the convention and from staff.

"There were a lot of sad parents who had to explain to their kids," he tells WW. "We've received complaints every year. Every year this costume group shows up and every year we have to talk to them and make sure there's no swastikas, and that's why we just said, 'Hey, we shouldn't have to deal with this every year.' It's a bit of a crazy time."

The costumes were also noted by writer Claire Napier in a post for Women Write About Comics. Napier writes:

"Speaking of Rose City Comic Con, how 'bout them 'ironic' nazis? Cosplayers wandering round in 'satirical' (satirising what? This, as yet, remains unreported) Hello Kitty-branded Nazi officer uniforms."

Brister says he's seen an uptick in Nazi cosplay costumes at conventions around the country this year, which might partly be because of the popularity of The Man In the High Castle, an Amazon show that explores what it would be like if the Nazis won World War II. He says the cosplay for the main character has blatant swastikas on it.

"It's still a Nazi uniform," Brister says. "Maybe they invested in a costume several years ago, and in the current political climate, it seems more tasteless than before."

He says that some people try to explain that costumes for the Red Skull and Hydra by saying they're from comic books, but he believes it's more important to address the concerns of those at the convention.

"We want to make sure everyone feels safe and welcome at the show," he says. "I'm hoping people just choose new costumes. We're just sensitive to things these days, especially in Portland."

Brister says nobody will likely receive a lifetime ban and that the policy will be changed to simply ask the person to leave and change their clothes.

"What we're trying to do is make sure people understand that we're serious about this," Brister says. "If you are a Nazi and you're a person full of hate, then stay home. But otherwise, we want everyone to come to the show. Nobody's going to get banned unless they're doing something so egregious we have no choice."