'The Flash': Barry will face Reverse Flash--but who is he?!

Even before the debut of The Flash, diehard fans had a pretty good idea about the show’s future uber villain. During Barry Allen’s (Grant Gustin) initial introduction on Arrow last season, the forensic scientist shared the tale of witnessing his mother being murdered by a blurry figure, a clear nod to DC Comics villain Professor Zoom, otherwise known as the Reverse Flash.

What’s more, when the spin-off began filling out its cast, Rick Cosnett was tapped to play Eddie Thawne, seemingly a play on the name Eobard Thawne, the alter-ego of Professor Zoom. If the producers hadn’t quite hit the nail on the head, the upcoming Dec. 9 episode is titled “The Man in the Yellow Suit.” In other words, we’ll finally see the Reverse Flash in the flesh, not just as a blur from Barry’s memory or a flash of yellow light threatening Joe (Jesse L. Martin) to drop the case or suffer the consequences.

“We’re building towards a confrontation between Barry and the Reverse Flash,” executive producer Andrew Kreisberg tells EW.

However, it sounds like viewers won’t find out Reverse Flash’s identity anytime soon. “Barry will actually get to come face to face with him, not just running with him, but standing face to face with him, looking at him,” Gustin says. “He’s vibrating, so he doesn’t know who he is. We don’t see his face. No characters see his face and the audience doesn’t necessarily see his face either, but Barry gets to hear him say that he killed his mom.”

So, who is the man behind the mask? Cosnett, the (too?) obvious choice, does his best to avoid answering any questions that may incriminate him. “The thing about this show is we always want people to be surprised,” he says. “We just don’t want any plotlines getting out before the episode comes out.” So, has it been hard for the actor with the mounting pressure of fan expectations? “Not really,” he adds. “It’s exciting. When a character has such a history, you get to bring all this reality to it and all these layers. I just wanted to make him a human being, first and foremost. Then, from there, it’s fascinating to see how that progresses.”

Though Cosnett has seemingly been trained well, Gustin is quick to point out that the producers may have some tricks up their sleeves. “I didn’t even remotely see coming what Andrew Kreisberg told me is going to be one of the turning points with that storyline,” Gustin says. “I’ve heard so many theories surrounding Reverse Flash that are all interesting. I was like, ‘Oh, I know what’s going on,’ but literally no one knows what’s going on. Anyone who thinks they know what’s going on is wrong. I’m in the in and I thought I knew, but Andrew told me and I was like, ‘Holy crap.'”

“I like to think that we’ve done a good job on both shows of meeting fans’ expectations and subverting them,” Kreisberg says. “The show has to appeal to everybody. It can’t just appeal to comic fans and it can’t ignore them either. We’re always treading this fine line of trying to bring something new, honoring what’s always been done and turning it into this brand new thing.”

Suffice it to say, confirming the horrible truth that this villain did, in fact, kill his mother will cause Barry to lose “his mind a little bit,” Gustin says. “Following that, we have a huge fight that we shot in the football stadium in Vancouver. That was huge.”

But Barry won’t be alone in this fight. “Episode 9 is really cool because it’s everybody coming together to help,” Kreisberg says. “Cisco [Carlos Valdes] and Wells [Tom Cavanagh] devise a trap to bait the Reverse Flash and they enlist the help of Tina McGee, played by Amanda Pays from the original Flash show. It becomes an interesting new combination of characters.”

“It’s fun when you finally see our team confronting the Reverse Flash and seeing everybody’s reactions, because he is the devil, in a way, to the show,” Kreisberg continues. “When you finally see everybody confront him, it’s really scary. It’s certainly the scariest thing we’ve done on the show. Our tone note to Tom, Jesse and Grant was to pretend you were in the room with the alien from Alien. You should all be that scared.”

But allowing everyone in on the action also means they’re all in the line of fire. “Reverse Flash, in terms of his powers, has such a potency about him,” Valdes says. “The magnitude of these powers is so hazardous and so dangerous that it’s a real threat for these characters.”

The Flash airs Tuesdays at 8 p.m. ET on The CW.