The Flash: Tom Cavanagh on How Negative Part One "Reboots" Barry and Thawne's Rivalry

The Flash's Season 8 finale airs next week which means that this week's penultimate episode, "Negative, Part One", had some major developments. As was teased in the previously released episode synopsis, the episode saw the cause of Iris West Allen's (Candice Patton) time sickness revealed, but also saw some stunning developments when it came to Barry Allen's (Grant Gustin) long-running conflict with Eobard Thawne/Reverse Flash. Now, with fans still reeling from the surprising developments of the episode's final moments, Tom Cavanagh breaks down how this week's episode "reboots" everything for the hero and the villain.

Warning: spoilers for this week's episode of The Flash, "Negative, Part One" beyond this point.

Thanks to some machinations by the Negative Still Force/Deon (Christian Magby), the episode saw Cavanagh's Thawne resurrected through the body of the "new" Eobard Thawne (played by Matt Letscher). Literally, as in after Iris was killed by Barry's lightning, she turned to what appeared to be temporal energy which then entered the newly powered Eobard and prompted Thawne to tear his way out in a truly horrifying moment of visceral horror. The result is that Reverse Flash is back and stronger than ever which means his fight with Barry has kicked back into high gear and Cavanagh told, it's a reboot of more than just the villain, but also their battle, taking them back to the "purest form" of the series' storytelling.

"I think broad strokes and big picture, there's a lot of intricacies to it, if I were to get into the minutia, but overall will these to ever be satisfied? It takes different forms, but … this versus season one, the battle always seems to be reminiscent of itself, and I think the reason that we keep telling these stories is that they work with these two," Cavanagh said. "There's an intimacy when you have the hero go up against the arch villain and so the Reverse Flash reboot, in broad strokes, it means they get to keep doing that."

Cavanagh also said that he feels like the way the series pulled off this particular twist, really worked for the story.

"When you come down to it, it's season one again, in many ways," Cavanagh said. "It's the mystery and the horror of finding out that the thing that you thought you trusted, you can't trust because evil lurks there. It's the same thing. We're [eight seasons along] but ultimately that very moment you're talking about is reminiscent of when I put my hand through Cisco Ramon's chest, and it's scary, and horrifying, and visceral, shocking, and I don't use visceral as a pun there."

He continued, "But those are the moments that you want to tell, but they work the best when you're not doing them to show them up, and when they're supported by story, and I feel like in season one, that was definitely completely supported by story, and I feel it's the same the same thing with those moments that you're talking about here. Those moments work best when they're supported by story and the writers' room was prepared with the story and so I think it worked."

The Flash airs Wednesdays at 8/7c on The CW.