Casting news and details provided by The CW about The Flash’s Armageddon crossover event shed light on what to expect from both the story and the villain the heroes will be facing. Unlike the annual crossovers that preceded it, Armageddon stands out as a story exclusive to one show, but it will involve multiple guest appearances from outside Barry Allen’s corner of the Arrowverse.

The Flash season 8 will launch with Armageddon - a crossover spanning across five episodes - when the series returns on November 16. During this time, Team Flash will be meeting up with a number of established Arrowverse heroes and villains, including a few from shows that have ended or are ending, like Black Lightning, Supergirl, and Arrow. Ryan Choi (Osric Chau) from Crisis on Infinite Earths, Batwoman (Javicia Leslie), Sentinel (Chyler Leigh), Damien Darhk (Neal McDonough), Atom (Brandon Routh), Mia Queen (Katherine McNamara), and Black Lightning (Cress Williams) are all confirmed to have roles in The Flash crossover. Tom Cavanagh’s Reverse-Flash, who was just brought back into play in the season 7 finale, will be along for the ride as well.

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According to an official description, Armageddon will pit Team Flash and Barry's Arrowverse allies against a “powerful alien threat” that will come to Earth under “mysterious circumstances” and threaten “the fate of humanity.” Reportedly, the mastermind behind this scheme is Despero, who will be played by Tony Curran. In DC Comics, Despero is an alien warlord seeking to conquer the entire universe and an old villain of the Justice League. Because of his impressive power level, it usually takes whole teams of superheroes to take him down.

Despero attacks Martian Manhunter.

Despero’s inclusion in Armageddon fits with what’s been said about the plot. Given his long history of trying to conquer the world in DC Comics, his arrival on Earth-Prime could very well threaten all of human civilization. Also, there’s a strong likelihood that Armageddon will be about a lot more than just saving the planet from aliens. It could also turn out to be a large-scale time-travel story. Though it’s not clear yet if there’s a connection, the crossover shares its name with Armageddon 2001, a DC Comics crossover event and time travel mystery about the identity of a villain called Monarch, who tried to rewrite time so that he could rule the world. If there’s any link between the two, Despero could have a similar plan in the Arrowverse.

Adding evidence to the idea that time travel may be at the heart of The Flash’s Armageddon are the casting of Mia Queen and Damien Darhk. Unless Darhk is somehow resurrected (again), it’s likely that he enters the picture through the timestream, just as he has done on Legends of Tomorrow. As for Mia, she’s living in the future, which is where Arrow left her back when there was a plan for her to star in Green Arrow and the Canaries. With both characters being in “Armageddon”, it does appear that time travel will indeed play a role in Team Flash’s conflict with Despero. That could be an interesting approach, especially since most crossovers have focused on alternate Earths. Armageddon could be the first to hinge on time travel, which has long been important to Flash’s story.

More: How The Flash Season 7 Abandoned Its Reverse-Flash Return Setup