The Flash showrunner reveals everything he couldn't fit into the final season

Warning: This article contains spoilers for the series finale of The Flash, "A New World: Part Four."

The Flash brought back its biggest villains in the series finale before Barry (Grant Gustin) and Iris (Candice Patton) got their happily ever after at the end of the chaotic, jam-packed, four-part series finale. But it turns out there was even more drama, action, and twists that showrunner Eric Wallace couldn't fit into the shortened final season — and he's ready to spill all the details!

When speaking to EW in our latest cover story (prior to the writers' strike), Wallace revealed everything he wanted to include before The Flash ended for good, but ultimately had to be cut. "I knew ahead of time what story I wanted to tell, and we're actually telling the story that I wanted to tell in the 200th episode, had we gotten there," he says. "Sadly, we did not. I originally had a two-year plan involving seasons 9 and 10, but the second half of what would've been the 200th episode was just too good, so I dragged it and pulled it all the way into the series finale and then put some new stuff on top of it to create a new story."

While he's satisfied with how The Flash ends in episode 184 instead, he still can't help but mourn all the ideas that never came to fruition. "What was disappointing is there were a couple of heroes and a couple of villains that will just never see the light of day in the Arrowverse, unfortunately, because we had to put all of our energy into Barry and Iris — we've got to fit two years' worth of Barry and Iris in one season," he explains.

Below, Wallace breaks down all the ideas, characters, and storylines he wanted to bring to The Flash in the final season that just didn't work out — including one last epic crossover event.

The Flash -- “A New World, Part One” -- Image Number: FAL910fg_0018r -- Pictured: Grant Gustin as The Flash -- Photo: The CW -- © 2023 The CW Network, LLC. All Rights Reserved.
The Flash -- “A New World, Part One” -- Image Number: FAL910fg_0018r -- Pictured: Grant Gustin as The Flash -- Photo: The CW -- © 2023 The CW Network, LLC. All Rights Reserved.

The CW Grant Gustin on 'The Flash'

Chester's mysterious enemy

Wallace points to an unresolved mystery from season 8 that he wanted to bring back in a bigger way if he'd had more time. "When I heard [the final season] was only 13 episodes, suddenly so many things just went out the window at that point, like we had a huge storyline that was going to involve Chester [Brandon McKnight] and Allegra [Kayla Compton]," he says. "They've finally kissed, finally fallen in love, all that good stuff, but they had their own insane storyline in the middle of season 9 originally with a villain that we didn't even get to introduce."

Back in season 8, episode 15, Wallace planted the seeds for the villain. "There's a computer and a cryptic thing comes up and someone downloads all of Chester's files," he says. "That was us setting up the middle graphic novel villain for season 9. Sadly, that doesn't get resolved anymore because the whole storyline had to be cut."

Khione's origin story

Danielle Panabaker's original season 1 character, Caitlin Snow, returned by the end of the series finale, after goddess Khione took over her body for all of the final season. But Wallace intended to expand Khione's origin story even further.

"With Khione, although it worked out great, I had originally pitched it to Danielle Panabaker as a two-year story, and suddenly I didn't have two years to tell her story," Wallace says. "So the whole first half got thrown out. It was supposed to start with who comes out of that crystal coffin, right? We had to change so many things. Where we ended up is equally as shocking and surprising and emotional as we would've gotten to in season 10, but we did lose some of the minutia that I think would've been very enjoyable for the fan base and for us as writers and directors."

the flash finale ep 913
the flash finale ep 913

Bettina Strauss/The CW Danielle Nicolet as Cecile Horton , Jon Cor as Mark, Danielle Panabaker as Khione, Kayla Compton as Allegra Garcia, Brandon McKnight as Chester P. Runk and Grant Gustin as Barry Allen on 'The Flash'

The crossover events that never happened

A long comic book arc that Wallace wanted to adapt into the final epic crossover event was The Blackest Night, a mini-series first published in 2009 involving the Green Lantern corps.

"Back in season 8, we set up The Blackest Night storyline with Deathstorm," Wallace says. "When Deathstorm was defeated, the emotional vibrations went all the way back to the Netherverse and another dimension to Nekron, who's right out of the comic books. I wanted to have one final, big, huge epic crossover, getting everybody — if you're on a show or not — back together for that storyline. What that would have allowed me to do is bring back characters that are dead."

Wallace intended on bringing characters together from The Flash and Superman & Lois, as well as Titans and DC's Stargirl.

"The idea was to get them all together to stop Nekron and all his Black Lanterns, which I'm sure Geoff Johns would've loved because it's his creation," he says.

Another massive graphic novel Wallace wanted to take on is The Forever War. "That's one of these crazy things that I've been hinting at, which is very tied in with the Chronarch," he says, referring to the rulers of the 64th Century. "We've been hinting that the Chronarch would be back in some way, as early as season 7 when Abra Kadabra [David Dastmalchian] mentions to Barry, 'The Chronarch is coming and is going to mess up your life.' It has to do with Barry and Iris because eternity is falling apart and forever is getting taken away. That would've kicked off season 10 with a couple of special guest stars that we would have seen."

Returning fan-favorite characters

Wallace also reveals he wanted to bring back Jordan Fisher as Barry and Iris' second child, Bart Allen, but he was starring in Broadway's Sweeney Todd at the same time the series finale was in production. "The timing just couldn't have been worse," he says. And he had an idea to bring back former Flash stars Tom Felton as Julian Albert and Shantel VanSanten as Patty Spivot, and reveal that they've become a married crime-fighting duo named Hot Pursuit. "How cool would that have been?" he adds.

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