In a surprising confirmation of a long-standing fan theory, Zack Snyder revealed via the social media network Vero this morning that General Calvin Swanwick (played by Harry Lennix in Man of Steel) was intended to be revealed as Martian Manhunter in a scene from Justice League. Sharing some storyboards on his Vero account, Snyder captioned one "This is something that you probably didn't know," and in another said that he had filmed the entire sequence before exiting the film, except for Lennix's part, which he intended to shoot in Los Angeles but never got to. The character never appeared in the finished film.
While Martian Manhunter is his own character and one of DC's most storied alien adventurers, the character has been a regular supporting character in live action for his Kryptonian super-friends. He first appeared on Smallville, played by Phil Morris. Later, he showed up on Supergirl, played by David Harewood.
Zack Snyder shared these storyboards today. One of long suspected rumors has turned out to be true. General Swanwick from Man of Steel is confirmed to be The Martian Manhunter J'onn Jonzz! pic.twitter.com/h5Cpkv8diX— ReleaseTheSnyderCut (@RTSnyderCut) October 5, 2019
Snyder is notoriously interactive with his fans and supporters on Vero, and has shared insights about, and sometimes unseen content from, his DC movies in the time since departing the shared universe.
While Lennix had a relatively minor role in Man of Steel, rumors have long persisted that he would have been a major player down the line. The actor was chosen by Warner Bros. to be the one to help announce Batman v Superman: Dawn of Justice at 2013's Comic Con International in San Diego.
Justice League Part One and Part Two were announced at the same time, with Snyder supposedly filming them back to back. That did not last long, though. Snyder eventually, famously, either left Justice League or was forced out shortly after the death of his daughter. But even before that, a set visit during production on the film included quotes that indicated that Part Two was not guaranteed to happen, and might not happen with Snyder even if it did. Conventional wisdom says that before he exited the movie, the plan was to build a trilogy of films, but even at its most bullish, Warner Bros. only announced the two before things started to change. As for Eisenberg, he was built up in Batman v Superman, but appeared only for a few moments in a post-credits scene in Justice League.
When Justice League was released in 2017, with Snyder as the sole credited director of the movie but everyone knowing that Joss Whedon had overseen significant reshoots and dramatically cut the film back from its original runtime to meet studio demands, the film was relatively well received -- as long as the bar you are using for that statement is the one set by other DC movies, which up to that point had been largely hated by critics and divisive among fans.
Its poor box office performance cemented what many fans already expected: Snyder was done with DC films for the foreseeable future, and Justice League Part Two was shelved indefinitely. It seems that the best, if not only, chance to see new, Snyder-directed DC content for the foreseeable future would be if Warners releases a the Snyder cut of Justice League -- regardless of how long a shot that might be.