Arrow Creator Says "Crisis on Earth-X" Nearly Ended the Arrowverse Crossover Events

We are just days away from the biggest Arrowverse crossover event to date, the epic five-night "Crisis on Infinite Earths". The event, an Arrowverse adaptation of the classic comic book event series of the same name, is one that fans of The CW's connected universe of DCTV series have been hoping for since it was first teased during The Flash's series debut in 2014. Everything we've seen teased thus far about "Crisis on Infinite Earths" hints that the crossover will be everything that fans hope, but when it comes to crossovers past, there's another "Crisis" that Arrow creator Marc Guggenheim says is the "gold standard" of the Arrowverse so far and nearly ended the idea of the crossover entirely -- 2017's "Crisis on Earth-X."

As fans may recall, "Crisis on Earth-X" saw the leaders of the Nazi-ruled Earth-X come to Earth-1 -- crashing the wedding of The Flash's Barry Allen and Iris West in the process. It turns out that Earth-X is a dystopia in which World War II was won by the Nazis. Now, generations later, it is ruled by a new Fuhrer -- Dark Arrow and his wife, the Kryptonian Overgirl. As for why they've come to Earth-1? It turns out that they're after Supergirl as it's revealed that Overgirl is dying from disproportionate solar irradiance in her heart and the big evil plan is to weaken Supergirl and take her heart to save Overgirl.

"Crisis on Earth-X" covered all of the then-four Arrowverse shows and packed in more than 15 total superheroes to tell the tale, and even went so far as to bring characters who would go on to appear in CW Seed's animated Freedom Fighters and it's something that Guggenheim told Entertainment Weekly was just so big that the network had to convince them to do future crossovers.

"It made sense to just organically play with the toy you already have," Guggenheim said. "That's another element of universe building and universe creation: A lot of the ways you create inter-connectivity in your universe is, you always ask yourself, 'Am I reinventing the wheel or is there a piece on the chessboard that is already in play that I can use?'" He continues, "In the case of Earth-X, Earth-X was something that was already introduced in an animated series that's in canon in our universe. So why not make use of it in this doppelgänger idea that we had for the crossover?"

"It killed all of us. We were feeling the effects of it literally a year after," he further explained. "The network had to really, really convince us to do another crossover because after 'Crisis on Earth-X,' we were all pretty burned out. We were like, 'Can we take a break and then come back for Crisis on Infinite Earths?' And The CW was like, 'No, no, don't worry. It doesn't have to be all four shows. It can only be three hours.'"

Last year's "Elseworlds" ended up being that three-hour "break" of sorts, but it also opened the door to the coming "Crisis" and it's that event that will the beloved story come to life in an epic way. Guggenheim told ComicBook.com previously that the event will have some very true-to-comics moments.

"Basically, we're gonna begin — this is an exclusive — we're gonna begin the way Crisis on Infinite Earths the comic begins, which is the destruction of various parallel universes. And the goal is for us to adapt key moments from the comic, those seminal moments," Guggenheim told us.

"In fact, yesterday I pitched to the network what the story was going to be and the best part of the pitch, we have a board that DC made up for me, which is covers from key issues of Crisis on Infinite Earths. And we're like, 'We're gonna do our version of this, we're gonna do our version of this, we're gonna do our version of this.' Our goal is, the thing we've been saying, is we're going to make a list of 100 cool things that we want to do. And even if we only get to do 50, we're still doing 50 cool things."

"Crisis on Infinite Earths" kicks off on Sunday, December 8 on Supergirl, runs through a Monday episode of Batwoman and that Tuesday's episode of The Flash. That will be the midseason cliffhanger, as the shows go on hiatus for the holidays and return on January 14 to finish out the event with the midseason premiere of Arrow and a "special episode" of DC's Legends of Tomorrow, which launches as a midseason series this year and so will not have an episode on the air before the Crisis.