It’s long been assumed that Justice League would feature an appearance by Batman V Superman baddie Lex Luthor, to Earth in the first place.
The main cast for the film includes all of the aforementioned Justice League superhero actors, as well as Ben Affleck (Bruce Wayne/Batman), Amy Adams (Lois Lane) and Henry Cavill as Clark Kent/Ka-El/Superman… once he recovers from being “killed” by Doomsday in Batman V Superman, of course.
It also turns out that a key supporting player in the Wonder Woman solo film (making their DCEU debut in that movie) is likewise part of the Justice League ensemble.
While seemingly every member of the DC Extended Universe version of the Justice League technically showed up during this year’s Batman V Superman: Dawn of Justice, next year’s Justice League will serve as the true introduction to Arthur Curry/Aquaman (Jason Momoa), Barry Allen/The Flash (Ezra Miller) and Victor Stone/Cyborg (Ray Fisher) as they exist in the DCEU.