New information coming out of Lego, who have a licensing agreement with Warner Brothers and DC Entertainment for the upcoming Superman reboot Man of Steel, suggests that Black Zero may appear in the film.
There are a couple of incarnations of Black Zero, but the most likely one (if you believe the fan press who have picked up the news) to appear onscreen would likely be the supervillain directly responsible for the destruction of Superman's homeworld of Krypton, from where the film's established villains (General Zod and his Phantom Zone villains) also originate. In the comics, he was essentially a planetary saboteur who came to Earth hoping to do the same thing to Superman's next home.
The rumor comes from the fact that, among a list of Man of Steel-, The Dark Knight Rises- and other movie-themed Lego sets coming soon, there's a playset called "Superman Black Zero Escape".
There might be a relationship here to earlier rumors that the Phantom Zone would be called the Black Zone in Man of Steel, a break with tradition that many fans found puzzling. The idea of a "Black Zero Escape" could imply that the zone is named after its most famous inhabitant, and that he gets out at some point. This interpretation of the title would also explain why we haven't heard from him until now; maybe Zod and company are the actual villains for the film, but they're all pawns in a larger game whereby Superman opens the "door" to the Black Zone and allows Black Zero to escape. It would work well to set up sequels and/or a Justice League film, and the "overlord pulling the strings" trick obviously works pretty well in superhero movies--just ask Thanos.
Still another explanation for all of this is that in some iterations of the mythology, the Black Zero organization is a terrorist group in Krypton. If director Zack Snyder were to rewrite history a little bit to make Zod and his followers members of the organization, it could explain the name of the playset without actually changing any of what we know or think we know about the film.
A similar twist (especially since Zod is a general, after all) would be to incorporate the Black Zero Unit that one version of the mythology had in the Kryptonian military. In Smallville, General (then Major) Zod led battle against the Black Zero Unit, so it's worth stopping to take a breath and question whether this is really that much of a game-changer.
Lego may seem an odd source of information, but play sets based on The Amazing Spider-Man and The Avengers have revealed details that were later confirmed in key scenes from the films.