Arrowverse Crossover: Everything You Need To Know About Elseworlds

Every crossover needs a dastardly villain that is so evil that one superhero simply isn't enough to stop them. In the past, unstoppable threats such as Vandal Savage and evil doppelgängers have been deemed worthy enough to unite the Arrowverse's version of the Justice League and, this year, that honour goes to Dr. Deegan.

Actor Jeremy Davis has been cast as the character, who is a doctor at Arkham Asylum that is described as being potentially more crazy than the inmates he treats. Whatever unspeakable deeds he commits, it is more than enough to draw the attention of Green Arrow, The Flash and Supergirl - all of whom will turn up in Gotham City to stop him.

Given Arkham's location, it's entirely possible that Deegan is responsible for the eventual meeting between Batwoman and the three Arrowverse stalwarts.

Another interesting note is that Nora Fries is also set to appear (portrayed by Cassandra Jean). As she is a Batman character, we have to wonder if she'll be involved in Deegan's crazy plans, and if it could lead to the introduction of a major villain like Mr. Freeze.