According to the Latino Review, sources have leaked the big bad that will bring Superman, Batman, Wonder Woman, Flash, Green Lantern, and the other members of the Justice League together. This bad guy can’t be just another lackey or regular villain. This threat has to be large enough that no singular hero could handle it.
The big villain of the DC Universe (new or old 52) will always be Darkseid. This will not be the lame version from Smallville. They will fight a “New god” with deadly Omega Beams.
There is no guarantee that these sources are correct on this but it makes the most sense. There are not too many threats that Superman can’t handle by himself. Darkseid is powerful enough to challenge the Justice League.
