Although it may seem like a lifetime ago, it's actually been less than three years since director Zack Snyder revealed the first look at Jason Momoa as Aquaman in Batman v Superman: Dawn of Justice. Released in February 2015, the image of the Game of Thrones actor as DC Comics' grim Sea King was emblazoned with the slogan "Unite the Seven," which immediately ignited speculation about who those seven might be: Might Green Lantern join Batman, Superman, Wonder Woman, Aquaman, The Flash and Cyborg in Justice League, officially announced just four months earlier?
Momoa's Aquaman, Ezra Miller's The Flash and Ray Fisher's Cyborg had only the briefest of cameos in Batman v Superman, which included no sign of a Green Lantern, Hal Jordan, John Stewart or otherwise. And by the time the marketing began to ramp up for Justice League, "Unite the Seven" was all but forgotten by everyone but fan artists, replaced first on posters by "Unite" and then, briefly, by "Unite the League." That, of course, raises the question of why Warner Bros. abandoned "Unite the Seven."
We might theorize that the slogan was too esoteric, holding little meaning to anyone beyond DC Comics fans, who would know there were seven founding members of the Justice League of America (Superman, Batman, Wonder Woman, Aquaman, The Flash, Green Lantern and Martian Manhunter). Or that the studio, or Snyder, changed plans for the film or the larger DC Extended Universe, dropping Green Lantern before production began.
But there's another, far more likely, option: "Unite the Seven" never had anything to do with the Justice League; instead, it was always about Aquaman.
The clearest indication of that arrives in a recent interview in which Momoa offered broad details of director James Wan's film. “In the story, we’re going to see a couple different younger versions of me," the actor said. "And even before I was born, so you’ll know where my mother came from, Atlantis. We’ve got to establish seven different kingdoms and the threat.”
It's that final sentence that's most pertinent, of course, as it's presumably a reference to DC Comics' seven ancient kingdoms of Atlantis -- also known as the Seven Seas -- four of which were destroyed centuries ago when the grief-stricken King Atlan sunk the fabled land in the midst of a civil war. Only Xebel, the Trench and Atlantis itself remained, each evolving separately, with the inhabitants of the first two awaiting the return of their "true" ruler. That day arrived when Atlan was inadvertently awakened centuries later in Antarctica by Aquaman, and arose as the Dead King, determined to reclaim his throne.