Justice League star Harry Lennix had no idea his ostensibly human character, General Swanwick, was actually meant to be the superhero Martian Manhunter. Lennix originated the role in director Zack Snyder's 2013 film Man Of Steel, where he served as a top military official wary of Superman's initial arrival on the public stage. He was something closer to an ally in Snyder's 2016 followup Batman V Superman: Dawn of Justice, where he'd been promoted to Secretary of Defense.
Swanwick didn't actually appear in the version of Justice League released to theaters in 2017. That version was completed by Avengers director Joss Whedon after Warner Bros. parted ways with Snyder midway through production. Spurred on by a massive fan campaign on social media and the overall failure of Whedon's cut, the studio is allowing Snyder to complete his vision of the film with a sprawling four-hour cut on HBO Max. Lennix returned to shoot new scenes as Swanwick for Snyder's cut.
According to an interview with Variety, Lennix didn't know Swanwick was intended to be Martian Manhunter until Snyder shared storyboards of the hero morphing into Swanwick and Martha Kent.
I’m pretty sure that’s exactly what I found out. I don’t think there was any sort of advanced word. There are a lot of people who intuited it somehow, like fans bouncing that idea around. So I don’t know if somebody knew about it outside of Zack before that. But I did not know until I saw that storyboard.
This is the latest indication that Snyder's version of Justice League might actually turn out to be a very different movie than the one that bombed at the box office in 2017. This is in addition to new villains like Darkseid (who only gets a mention in the theatrical cut) and Jared Leto's Joker (who was not in the film at all), and scenes including supporting characters like Ryan Choi and Iris West who were cut from the theatrical release.
Martian Manhunter is generally one of the founding members of the Justice League in the comics, so it's interesting that he's getting at least a nod in the new cut of the film, though Lennix clarifies that he doesn't have a particularly significant role in the film. Martian Manhunter is, as one may have guessed, from Mars, one of the last survivors of a decimated civilization from the red planet. He has most of the same powers as Superman, though is also telekinetic and is able to phase through solid matter. He's usually one of the most powerful, but also gentle and empathetic DC superheroes.
This will be a decidedly different version of Martian Manhunter, though fans shouldn't be surprised; Snyder has made a habit of zigging when audiences expect him to zag with his DC films, and Justice League will likely be no different. That has led to some incredibly polarizing reactions from fans, but people can't say Snyder doesn't have a style all his own, and it'll be interesting to see how Martian Manhunter fits into his iteration of the DC Universe.
Source: Variety
