Superman has been one of Batman's best allies and greatest foes throughout his career as the "World's Greatest Detective." In Arkham Knight, many in-game items refer to the line between the Man of Steel and the Dark Knight.

Listen to Bruce's answering machine in Wayne Tower to hear several messages from Lex Luthor, who is interested in purchasing the Applied Sciences division of Wayne Enterprises - apparently Bruce has been avoiding his calls. Scattered all over Gotham are billboards for the mega-corporation that serves as the main infrastructure for Clark Kent's nemesis Lex Luthor. Several thugs can be heard lamenting the state of Gotham, adding that all it needs now is for a certain caped freak to come flying in.