The Flash showrunner Eric Wallace recently confirmed that the series was building to a "Blackest Night" storyline in Season 10.
In an interview with The Nerds of Color, Wallace revealed that an adaptation of the DC Comics crossover was in the works until The CW announced that The Flash would wrap up with its ninth season. "We were gonna do all kinds of things," he said. "I can tell you we were going to tackle the "Forever War" storyline, which is something that I [came] up [with] for Season 10. That was going to be a season opener, and we've been hinting at it… I wanted to do a full-on crossover with as many characters as possible. The "Blackest Night" storyline that we started hinting at last year with Diggle and the box."
"So yeah, it kind of bums me out that we're not going to do that," Wallace continued. "I wanted to bring Despero with his alien friends and have a full-on alien invasion. That would have featured the Justice League at the Hall of Justice coming in and helping Barry. We're not going to do that either." The showrunner added that he initially developed a two-year plan for The Flash that mapped out Barry Allen's journey in Seasons 9 and 10 and would've culminated in an "incredible" 200th episode. Wallace was later informed that Season 9 would be The Flash's last and that it would only run for 13 episodes, forcing him to streamline his intended narrative.
The Flash Boss Talks Legends of Tomorrow
Among the content cut from The Flash Season 9 was an episode meant to resolve the cliffhanger ending of DC's Legends of Tomorrow, which the CW canceled in April 2022. According to Wallace, this storyline would've shown the Legends escaping their imprisonment, and might even have run across two episodes. "We get them back, we get them out of time jail, all these good things, Booster Gold, etc, etc," Wallace said. "When we found out we only have 13 episodes, that was no longer possible." He went on to express regret that The Flash Season 9 wasn't able to deliver a satisfying Legends of Tomorrow conclusion, but emphasized that the season's limited runtime meant he had to prioritize the Barry/Iris relationship above all else.
That said, Wallace subsequently stated that the Legends of Tomorrow characters will appear in some capacity in at least one episode of The Flash's ninth and final season. What's more, the showrunner refused to rule out a greater role for the Legends than what is already planned, noting that the series finale is still being written.
The Flash Season 9 is now available on The CW and The CW app, with new episodes dropping Wednesdays.
Source: The Nerds of Color