Thanks to TV Line , we now have the descriptions of three "mystery" characters who will join Brandon Routh (The Atom), Caity Lotz (The Canary), Wentworth Miller (Captain Cold), and Victor Garber (Dr. Martin Stein) in the untitled Arrow/The Flash crossover which has been described as a team-up show of sorts. There's no word on the identity of these characters, but the site has put forward a few educated guesses based on the descriptions offered. Share your theories below.

Firstly, there's "The Traveler", and he's described as a "Han Solo-esque rogue who gets by with his charm, this hero hails from the future, and has journeyed back in time on a secret mission. His razor-sharp wit hides the pain of a man who has lived through serious conflict. He also harbors many secrets, always leaving both his teammates and the audience unsure of his true allegiances." They theorise that this is Rip Hunter, a "Time Hunter" who only uses that as an alias to stop his enemies from travelling back in time and killing him as an infant. Could he be the one who brings back Sara Lance by picking her out of an earlier point in time? They also suggest that Booster Gold is possible, but that wouldn't make sense when it's been said that these new additions have never been seen in live-action before. Even so, "The Traveler" definitely sounds similar to Booster.