While the rest of the Arrowverse is hanging out with Superman and Batwoman during the "Elseworlds" event, Legends of Tomorrow will have its own crossover episode, which will center on alternate realities.
It was announced over the summer that Legends of Tomorrow would be excluded from the 2018 Arrowverse crossover. Instead, the three-night event will only include Arrow, The Flash, and Supergirl. Titled "Elseworlds", the event will introduce Ruby Rose as Batwoman and Elizabeth Tulloch as Lois Lane as the heroes of the Arrowverse visit Gotham City for the first time. Tyler Hoechlin's Superman, who hasn't appeared since season 2 of Supergirl, will also be involved.
As reported by TV Line, at The CW's Fall Launch event, Legends of Tomorrow executive producer Keto Shimizu revealed that a special episode of Legends would air in the same week as "Elseworlds": "During the week that all the other crossovers are happening, we will essentially be crossing over with ourselves." The episode will incorporate "alternate time periods," which means that the Legends will get to meet alternate versions of themselves. White Canary actress Caity Lotz promises the "insane" episode will show different sides of the main characters.
The episode could have parallels to the 2017 Arrowverse crossover, "Crisis on Earth-X," where characters from all four shows clashed with evil versions of themselves, led by Stephen Amell's Dark Arrow. This time, however, the Legends could encounter versions of themselves across multiple realities, rather than just one. So while Green Arrow, Flash, Supergirl, and others will be dealing with alternative universes in "Elseworlds," the crew of the Waverider will apparently be faced with a similar problem of their own.
Since Legends premiered, the show has played a central role in each subsequent crossover event, making "Elseworlds" a first for the Arrowverse. It's possible that Legends of Tomorrow's absence is a good thing for the crossover, since a smaller cast can help the event focus on the characters and the story. It may also turn out to be a good thing for Legends as well. Legends showrunner Phil Klemmer previously stated that he was "happy to have to sit this year out" due to the fact that season 4 only consists of 16 episodes. Not being in the crossover allows the show to stay on track in terms of the main story without taking any kind of break from the overarching plot.
Legends of Tomorrow season 4 premieres October 22 on The CW.
Source: TV Line