WARNING: The following contains spoilers for The Flash Season 8, Episode 9, "Phantoms," which aired Wednesday, March 30 on The CW.

Team Flash has been put through the wringer throughout The Flash Season 8, with the recent episode featuring Chester P. Runk (Brandon McKnight) being targeted by a murderous new metahuman menacing Central City. Known simply as Black Flame, the shadowy entity took on the form of Chester's late father to claim S.T.A.R. Labs' resident tech expert as his latest victim. Ultimately, Chester saw through this illusion and survive, but the ordeal has greatly unsettled him and led him to ask challenging questions about himself moving forward.

In an exclusive interview with CBR, McKnight explained how Chester's confrontation with Black Flame will inform him moving forward in Season 8. He also shared how the cast and crew gave him the space to showcase a more emotionally vulnerable side to his performance and teased what fans can expect from Chester's role on Team Flash as the season continues.

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CBR: One of my favorite episodes in The Flash Season 7 was the '90s episode, where Chester meets his father. This episode feels like a sequel to that as Chester faces his unresolved feelings about his father in the form of Black Flame. How was it getting the script and seeing where you'd take the character here?

Brandon McKnight: It kept me up for a couple nights because I had no idea how I was going to do it, but it was very exciting as well. What you were saying is spot-on. It's like part two of the '90s episode, diving into Chester's psyche and deeper into the grief and despair, all the emotions he didn't know he had, and these irrational fears. Chester is such a logical human being so to believe some of the things he's believing in this episode and to come to some of the conclusions from that fear is really outside of himself.

When I read it, I was really excited and really scared. Then we started doing it and I got really excited again because this is the type of stuff that actors dream of, to have the character lose the rails a bit but also the development of the story and, with Chester, to see him go to a place we've never seen him go before. No matter what's going on in any episode, when Chester is having a hard time, he's always somehow able to muster a smile.

In this episode, every smile he sheds is forced, even after the fact that everything is figured out at the conclusion of the episode. Even then, he's so deeply affected by what he's experienced. I just thought it was a lot of fun to get to dive into this aspect of him that we've never ever really had the chance to do on this level before.

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Given the way Black Flame appears to Chester, that makes him the most personal antagonist he's faced so far. How will that inform him as Season 8 continues?

I think everything that Chester goes through, especially in terms of his grief and despair, just helps ground him because he is larger-than-life. He's this ball of energy. It helps ground him but it also gives him so much more confidence moving forward because he's still a new member of the team. Even though he's seen crazy things week-to-week, he's never really the target. To be the target of something and have to deal with it directly and it's not exactly something you can attack or physically defend yourself against, you have no choice but to grow to face this villain as we've seen so far.

There's a great deal of growth, from this episode on, in terms of his confidence and what he knows [that] he's capable of. This episode really doubles down on Chester's weaknesses and some aspects of himself that he didn't really know were there, that he didn't even know he had. He thought he was, to some degree, healed. To dredge back up these traumas and have to deal with them in this way, you can't help but to grow from that, and he really does. I think it shows that through the rest of the season as well.

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Last week's episode had Barry confront his own grief about losing his father, and this episode stands the chance of bringing Barry and Chester closer together. This season really is about facing and reconciling with grief.

Absolutely. I think it's really important that people see that, too, because with Cisco not being on the team, Cisco and Barry were two peas in a pod, they were best friends. To see the new guy in the chair building a relationship with The Flash, the guy he's idolized for so long, it's really important. I think it also helps benefit Chester's confidence moving forward as well. As we see in this episode, Chester's at crime scenes with Barry and having that, with Barry having to rely on him and Chester coming up with things to help Barry, not only as Barry Allen CSI but also as The Flash. There's just a great deal of growth in this episode, it should [have] the title "Chester's Growth." [laughs]

It's definitely something I noticed in the scripts and am really happy about and hope people catch on to and see, in regards to that relationship and what it does for the two of them, especially in later episodes in the season. We really get to see their relationship blossom and there's a great deal of trust that's built up there. One thing I really loved about this episode is throughout Barry peps him up in a way, even in the face of danger. There's just a great deal of stuff for Chester to carry moving forward.

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When you were sitting down with showrunner Eric Wallace coming off The Flash Season 7, where did you want to take Chester going into Season 8 as he emerges from the shadow of Cisco Ramon to be his own man?

That's exactly it -- how do we make Chester his own guy and not make it seem like we're trying to replace Cisco? You can't replace Cisco. It doesn't matter what character or actor you bring in, you're not going to replace what Carlos Valdes brought to this show. How do we make Chester his own thing? How do we show what Chester's about, his past, the humanity of who this guy is, and make him stand out as his own person? What's been going on right now throughout this entire season is exactly what we spoke about, making Chester an individual. He's the guy in the chair but he also serves the purpose of being the team's support system.

I drop this quote all the time -- when Eric was first telling me about Chester, he would say "[Chester] is the smartest person in the room and doesn't know it. He's also the most empathetic person in the room and doesn't know it." I think that's where his spot on the team really lies, being able to build whatever tools we may need but also being able to support people where they need. The stuff he goes through in this episode really reinforces his confidence in those aspects of himself.

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You've also got a lot of scenes with Kayla Compton in this episode and we've seen a possible future for you two in the Reverse-Flashpoint. How is working with her?

Those are my favorite days on set. We're chemistry, that's my homie. It's really easy to do scenes with her, particularly in this episode. Chester goes off the rails a few times and it's so good to have a scene partner who allows you to have the space to try some crazy, wild things and really get to try things. She was so kind and generous in letting me go where I think Chester would be going in the moment and [her] being a support system for both the character and in real life. I'm glad we have so many [scenes together] to come.

You have Stefan Pleszczynski as the director for this episode, and he's been working with you on The Flash for a while.

Stefan is the exact same way. He's such an artist. I hesitate to say he's an actor's director because he's also a very technical director, but he just allows so much space. He was so generous with me. If I wanted to go further with something, he'd let me do it. He's such a generous director. I love that guy and can't wait to have him back, he's so good.

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There are a lot of prime scenes for Chester in this episode, but where did you really want to focus and stretch out a bit to bring more of yourself to during filming?

The biggest thing I was focused on was just the overall arc of him not knowing what's going on -- seeing him go on from the evidence and things that are going on to then being directly affected by things and not knowing what to believe and what not to believe in terms of what he was seeing and experiencing. Then being in the full-blown thick of it all and then learning how to deal with the things he's experiencing and the feelings that are coursing through his body, that overall arc is something me and Stefan spoke a lot about.

In where he's coming from, how is he affected by what just happened, and how are we going to double down on that with what's happening right now? There were some things in the episode that were improv, the scenes where he's really in the thick of it, really thinking something crazy going and not knowing what's real while Allegra is trying to calm him down.

A lot of that was Stefan allowing me to try and see what I have and going for it. It's pleasure to get that kind of space and permission from a director on a show that's been on for so long. The show knows what it is and everybody on it is doing it so to be able to be given a little bit of space to go outside of that and do what I want to do and bringing it back to make it work for what the show is always a gift. I love Stefan for that.

Brandon, what else can you tease about Chester and his role on Team Flash moving forward in Season 8?

More of what we've seen, just in different ways. More growth -- he becomes a far more confident human being. You get to see his impact on the team and see how he is his own person with his own quirks and influences. You see his influence on the team moving forward, especially after this episode.

Developed for television by Greg Berlanti, Andrew Kreisberg, and Geoff Johns, The Flash airs Wednesdays at 8pm ET/PT on The CW.

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