Batman V Superman: 10 Biggest New Reveals From Zack Snyder's Live Commentary
9. Superman's Death Activated The Mother Boxes
In a deleted scene released after Batman v Superman arrived in cinemas, Lex Luthor was shown communicating with Steppenwolf and seemingly inviting him to Earth after the Man of Steel's demise. However, it turns out that there was actually more to his decision to return and track down the Mother Boxes than any of us suspected.
While Superman's death was indeed the precursor to Steppenwolf being sent back to Earth by Darkseid, Snyder explained that "If you really wanted to wake up a mother box, you would do it like this," referring to Superman's final scream. The Kryptonian's demise at the moment he and Doomsday died activated the Mother Boxes and made it clear the Earth had just lost a powerful protector.
That further explains why it was so important for the team to bring Superman back to life in Justice League. After all, if his fall was powerful enough to activate the Mother Boxes, then his rise would obviously help end their threat as well.
As it stands, this is just proof of another big change Joss Whedon made to Justice League with his reshoots as it's hard to imagine the Snyder Cut not referencing this in some way.