Could it be that the Arrowverse is actually connected to Christopher Nolan’s The Dark Knight trilogy?
The end of The Dark Knight Rises reveals that, to the world, Batman “died” in a blaze of glory in order to save Gotham City.
The Dark Knight is still largely seen as the gold standard for standalone comic book movies and, as far as the small screen goes, The CW has things locked down pretty right on the Arrowverse.
Specifically, an image of Bane’s mask that looks suspiciously identical to the one that Tom Hardy’s version of the character wore in The Dark Knight Rises.