[WARNING: This article contains SPOILERS for The Flash TV series]

When the producers of The Flash made the shocking decision to not just allude to the role played by Barry Allen's nemesis - Eobard Thawne a.k.a. Professor Zoom, 'the Reverse-Flash' - but include an overt cameo of the villain in the pilot episode. Add to that the presence of police detective Eddie Thawne, and many comic fans assumed they knew the show's plot before the second episode debuted.

Those assumptions have been challenged in the time since, with Eddie Thawne (Rick Cosnett) proving to be a hero in his own rite, and another shadowy character implied as a force for evil. Thankfully, viewers won't have to wait long for a bit more clarity. In another surprise, the Reverse-Flash was confirmed to appearing in Episode 9, "The Man in The Yellow Suit." The cast have finally offered some details about the showdown, and the mystery of the man under the yellow mask.

The cat was let out of the bag when the first set photos of the Reverse-Flash appeared, depicting the two speedsters in combat (apparently Barry's battle with Oliver Queen is just a warm-up). Star Grant Gustin now explains to EW that it's no coincidence the man wearing the yellow suit on set was a stuntman - not a member of the cast - but that even fans who think they know the villain's secret may want to exercise some patience:

"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... 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.

Following that, we have a huge fight that we shot in the football stadium in Vancouver. That was huge."

[Spoilers] Grant Gustin filming a fight scene on the set of 'The Flash' https://t.co/7tWdjyWfht pic.twitter.com/3bcRigkHv0— Grant Gustin News (@GustinNews) October 9, 2014

For his part, Cosnett explains that the devious future many see for his character isn't a concern just yet:

"The thing about this show is we always want people to be surprised. We just don’t want any plotlines getting out before the episode comes out... 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."

Executive producer Andrew Kreisberg admits that it's hard not to consider the expectations and assumptions made by fans. But it's safe to assume that a large part of the audience will need more than a comic book villain's appearance to thrill them; for them, it won't be Barry tackling the 'man inside the lightning' by himself, but along with his friends, working to capture the murderer with the help of prior Flash star Amanda Pays.

The stakes are high in doing Barry Allen's nemesis justice, but the producers have also committed to introducing both time travel and Gorilla Grodd by the season's end, so perhaps another blurry speedster is a relatively easy challenge. Either way, Kreisberg is confident that Reverse-Flash will be terrifying enough to get the job done:

"I like to think that we’ve done a good job on both shows of meeting fans’ expectations and subverting them... 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.

"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. 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."

Gustin also warns that he heard most of the theories rumored, but was as surprised as anyone to find out exactly what the writers have been building toward:

"I didn’t even remotely see coming what Andrew Kreisberg told me is going to be one of the turning points with that storyline. 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.'"

Since Thawne's own superspeed has been credited not to a bolt of lightning, but being removed from the flow of space and time itself, it's anyone's guess who could be responsible for the murder of Barry Allen's mother. Even if Thawne and Dr. Harrison Wells are present to help bring down the Reverse-Flash, it doesn't rule out their future selves; meaning the episode won't silence any popular fan theories. Although the fight isn't likely to solve any mysteries, the action itself should still prove worthwhile.

What are your thoughts on the identity of "The Man in The Yellow Suit"? Do Gustin's comments throw your own suspicions out the window, or do you have a likely culprit in mind? Share your thoughts in the comments.

The Flash airs Tuesdays @8pm on The CW.

Follow me on Twitter @andrew_dyce for updates on The Flash as well as movie, TV, and gaming news.

Source: EW