Jason Momoa as Aquaman
The rumour mill is in overdrive as another hero is scheduled to make an appearnce in Zack Synder's Batman vs Superman: Dawn of Justice. Looks like Jason Momoa from Stargate Atlantis and Game of Thrones will join Ben Affleck (Batman), Henry Cavill (Superman) and Gal Gadot (Wonder Woman) as Aquaman in the Justice League roster.
What little information we have to go on is that Aquaman is not happy about all the damage done to the Indian Ocean by the Kryptonians' World Engine from Man of Steel.
Batman vs Superman: Dawn of Justice opens May 2016