A couple of weeks ago Warner Bros. officially announced that Jesse Eisenberg’s Lex Luthor would appear in Justice League. One thing I didn’t even think of was that this means we’re going to get to see Zack Snyder’s take on Arkham Asylum in the DC Films universe! We got a small peek at it in Suicide Squad during a flashback between Dr. Harleen Quinzel and The Joker.
In the Ultimate Edition of Batman v Superman: Dawn of Justice, Batman tells Luthor that he’s arranged for him to go to Arkham Asylum in Gotham City. It’s very likely that when we first see Luthor in Justice League, it’ll be in a cell somewhere in Arkham.
To add some evidence to that speculation, several Justice League actors on IMDb have updated their profiles with their roles. “Arkham Guard”, “Arkham Guard 2”, and “Lex Luthor’s Guard” are all listed. And while anyone can edit an IMDb page similarly to Wikipedia, it’s more likely that these extras were just adding to their own résumés.