Appropriately for a member of the CW's "The Flash's" main cast of characters, Cisco Ramon's mind operates at two speeds: fast and faster. Since the young engineering genius joined S.T.A.R. Labs, he's contributed to the particle accelerator, constructed Barry Allen's costume, created the cold gun and improved Arrow's uniform. In short, Cisco has proven to be a vital member of Team Flash.

Recently, he resumed his rivalry with Hartley Rathaway, aka the Pied Piper. His co-worker, Caitlin Snow, also learned Cisco was partially to blame for the death of her fiance, Ronnie Raymond. However, that last "Flash" fact may be moot considering Ronnie returns with explosive new powers in tonight's episode of "The Flash," "The Nuclear Man."

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Carlos Valdes, who brings Cisco to life on "The Flash," spoke with CBR News about his character's darker impulses, the arrival of Firestorm and the Atom's armor. He also weighs in on the chances of Cisco following in his comic book counterpart's footsteps by becoming the metahuman sonic-powered hero known as Vibe.

CBR News: Between Caitlin, Dr. Wells and Cisco, there are a lot of big thinkers running around S.T.A.R. Labs. What, specifically, does Cisco bring to the table?

Carlos Valdes: Cisco brings a bit of engineer savvy. Dr. Wells (Tom Cavanagh) took Cisco under his wing and gave him a chance to work at this prestigious laboratory on this project, this particle accelerator. Dr. Wells saw something in Cisco when he brought him on. He wasn't just a really advanced talent at engineering -- Cisco also has heart, and a very curious personality. I think Wells saw that as a vital component in having a successful team of scientists at S.T.A.R. Labs. The way it's ended up for the most part is, Caitlin provides medical and biological expertise. Cisco has a more left-brain approach to the whole thing.

Viewers recently learned about Cisco's history with both Hartley Rathaway (Andy Mientus) and Ronnie Raymond (Robbie Amell). What did you enjoy about those personal revelations, and in what way did those details add another layer to the character?

It was really nice to be able to play with more antagonistic characteristics in terms of Cisco's attitude towards other characters in the show. So far, we've gotten a really good glimpse at Cisco's optimism and positivity and excitement. Aside from the cold gun incident, we haven't really seen much of his dark side. It was really nice to discover and play with a completely different attitude. You have to hand it to Cisco -- Hartley is such a dick. How can you not hate that guy?

Surprisingly, Cisco proved fairly skilled at physically fighting Hartley.

He's not an advanced fighter like Oliver Queen, but after growing up, Cisco might have seen an opportunity to learn how to defend himself given his status as an engineering nerd. So, he has a basic fundamental understanding of combat. That's what he brought to that sequence.

Tonight's episode sees the birth of Firestorm. What can you preview about the Cisco/Ronnie reunion?

Cisco is definitely expecting his brother. Ronnie was like a brother to him in the S.T.A.R. Labs construction of the accelerator. If he sees that face and hears that voice, Cisco expects that relationship with that person. Whether what Cisco gets back is actually the Ronnie Raymond he knows is a different question altogether.

Despite Caitlin's forgiveness, how guilty does Cisco still feel over what's happened to Ronnie?

Overall, Cisco has a long-term struggle with responsibility and accountability. What just happened in episode 12 is huge for him. That's something he's been bottling up for a long time. Seeing Caitlin react the way that she did in that episode, and seeing her trajectory throughout the season, he believes she has reached a new step in her grieving process. He might still feel a bit guilty, but a big amount of that weight that he was carrying has been relieved from that exchange.

Cisco will also lend a hand in investigating Nora Allen's murder. Why does Joe seek Cisco's assistance in the case?

Cisco has a technological expertise he can bring to situations. Joe is a detective, through and through. He has a detective mind. He has a detective way of operating. When you complement that with Cisco's technological prowess and attention to detail, that creates an amazing partnership. The two of them together to solve this mystery is actually a really good combination. It was a lot of fun, to be honest. That's probably one of the episodes that I had the most fun shooting so far. I'm excited to see how it plays on TV and how fans react to it because Jesse [L.Martin] and I love working together.

Felicity is returning to Central City, and Ray Palmer is coming along with her. What will Cisco make of Ray's Atom armor?

Obviously, I can't say too much, but there's somewhat of an emphasis on the relationship Cisco has with Ray. Fans can definitely expect to see how they connect over shared interests. As Carlos, working in the presence of the Atom suit was a hell of an experience. It's amazing.

What else is in store for Cisco in upcoming episodes?

Viewers can expect to see a bit of Cisco's background, where he comes from in respect to his family and how these formative experiences and relationships have influenced who he is and who he is becoming.

There's definitely some time travel stuff that I can't get too deeply into, but it's very exciting. Fans are going to have heart attacks. I don't know how they are going to make it through these next few episodes. Things are about to get crazy.

Francisco Ramon, aka Vibe, is a long-running DC Comics superhero. What kind of discussions have you had with the producers about exploring that legacy?

We definitely talked about where Cisco comes from, especially in the New 52 series, and how he works at a Radio Shack-type of store. He becomes Vibe very quickly after that. Even though the nature of this character is fundamentally informed by its comic book predecessor, it's ultimately a completely different person. That was one of the things that was so freeing about this project, is that we've basically built an original version of Cisco. He's massively informed by what's in the comic book, but he's still an independent individual. I like that fact that we've created something new.

So, will we see Cisco demonstrate sonic powers and adopt the Vibe identity?

We'll see. I don't know! [Laughs]