During a brief Twitter exchange with fans, Arrow co-creator Marc Guggenheim, who served as the showrunner on "Crisis on Infinite Earths," promised a "huge" announcement coming between now and when the crossover event begins on Sunday night at 8 p.m. ET/PT on The CW. Guggenheim gave no specifics as to whether the announcement was another piece of casting (the event already features numerous guest appearances from DC Comics heroes going all the way back to 1990's The Flash) or something more related to the story or a character fans didn't already know was showing up. At this point, though, it seems likely that any "huge" announcement is going to affect the fourth and fifth parts of the story, which will happen in January, since the first three parts are airing this week and are almost certainly already completed and locked for air.
It's also hard to think of a more "huge" announcement than getting the Supermen of Smallvile and Superman Returns, along with Kevin Conroy's Batman...but fans are already letting their imaginations run wild. The scope of "Crisis" has led to a lot of fun speculation.
You can check out Guggenheim's tweet (and the responses to it) below.
HUGE one coming. https://t.co/R30xD3n1r3— Marc Guggenheim (@mguggenheim) December 4, 2019
The event will bring together the heroes from multiple Earths to battle against the Anti-Monitor (LaMonica Garrett), a godlike villain who threatens to destroy all reality. In the comics, the story ended with the deaths of The Flash and Supergirl, and the destruction of DC's multiverse, leading to a single Earth with a complex history packed with hundreds of heroes.
The event will be the most ambitious thing DC has ever attempted in live action, bringing together characters from all six of the current DC Comics adaptations on The CW (Arrow, The Flash, Supergirl, DC's Legends of Tomorrow, Batwoman, and Black Lightning), along with characters and actors from the 1990 version of The Flash, the short-lived Birds of Prey, Smallville, Superman Returns, and the iconic 1966 Batman series.
“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. Black Lightning's midseason finale will have a "Crisis" tie-in as well, although unofficially.