When the Aquaman character poster for Batman v Superman: Dawn of Justice* hit I automatically assumed "Unite The Seven" meant the seven members of the Justice League. After all, the script is called Dawn of Justice, it's a prologue to a Justice League movie, and the Justice League has a traditional seven member core line-up.
But everybody else online seems to have immediately jumped to the idea that "Unite The Seven" means The Seven Seas. Does that make sense?
First of all, it's important to note that there's no such thing as "The Seven Seas." It's a saying, which often refers to all the world's bodies of waters. Of course the fact that there are no such thing as the seven seas in no way means Warner Bros marketing actually knows that, and just maybe they did put that tagline on there thinking it's clever.
Let's assume the tagline does refer to "The Seven Seas" - that would mean Aquaman's story in Batman v Superman is to unite those seven seas. To address this I will have to, in the most minor way possible, spoil a small element of BvS. You've been warned.
The problem with this is that, as of the shooting script, that was not even remotely the case. As of the shooting script Aquaman is barely even present, showing up only in a survey of metahumans by Lex Luthor and then again at the very ending, when Batman recruits him for the Justice League (see: Dawn of Justice as the title). Now, it's possible that as shooting has gone on and as the Justice League script has come into shape that something has been added to BvS. In the script Aquaman and Flash really just have cameos, but perhaps having the actors available and knowing where they're going in the future has allowed Zack Snyder and Chris Terrio to add in some tidbits about the future movies. Maybe the Aquaman movie will be about Aquaman uniting the undersea kingdoms. But in BvS? No way.
There simply isn't any room for Aquaman to have a storyline added to BvS, and if they attempted it I suspect it would be a disaster. With that in mind, and knowing that the film is a prologue to Justice League, doesn't it make more sense that "Unite The Seven" refers to bringing the team together? As I've said before, the only hitch in that is that I counted six metahumans in the Batman v Superman script, and there was a conspicuous absence of Green Lantern. Adding Lantern into the metahuman survey/final recruitment would be easy enough at any stage of the process, including during post-production, just as Marvel keeps adding post-credits bits very late in their process.
I'm sure a lot of people still think it's "The Seven Seas" - and maybe it is! But I suspect that the next character poster will have the same tagline. If it doesn't, Warner Bros has just dropped a major hint about the plot of Aquaman, since it has nothing to do with the plot of Batman v Superman.
* legitimately the title of a movie