Fan Casting ''The Watcher'' in Batman V Superman: Dark Knights of Tomorrow

In the Mid-Credits Scene for the film, we see a being as old as the multiverse itself watching over Earth-1610 through a portal, before closing it upon seeing what has occurred in that Earth over the past twenty four years. He opens up another portal, this time to Earth-49, before saying, ''The actions of Bruce Wayne will undo the multiverse if he isn't stopped. There's only one thing that could fight his Regime, and that... is the Regime of another.''