You might have recently come across a rumor that Steppenwolf is the main villain in Justice League: Part One. Birth.Movies.Death.'s Devin Faraci dropped that one. And now there's another rumor, from Heroic Hollywood's Umberto Gonzalez, which pretty much supports the first one.
Before moving ahead, be warned that the following content might contain SPOILERS for Justice League: Part One.
According to the latest scoop, Steppenwolf is indeed the big baddie in the November 17, 2017 flick. But he "won't factor into the story" until the movie's second half. While Devin suggested that Darkseid would appear at the end of the movie, Umberto claimed that he'd make an entrance right at the beginning, in a flashback sequence. Both do agree that we will feel his presence throughout the movie, but he won't have much to do himself.
Umberto suggests that in Justice League: Part One, Darkseid, who invaded Earth around 30,000 years ago, was subsequently driven away, along with his forces, through the combined efforts of three races – "the Amazonians, the Atlanteans, and Man".
Darkseid then returned to Apokolips, but he left three Mother Boxes behind here on Earth. These are what Steppenwolf, his uncle – and the military leader of Apokolips – is looking for.
Apparently, the Mother Boxes appeared in the deleted scene from Batman v Superman: Dawn of Justice titled Communion. We might have also seen one of them being used to transform Victor Stone into Cyborg in the movie's theatrical cut. You can check out the clip below!
Another Devin Faraci rumor suggests that Willem Dafoe plays an Atlantean in Justice League: Part One. According to the initial casting reports, his character is a "good guy" in the movie. Could he be playing an Atlantean king or leader during Darkseid's first assault? Who knows! This is nothing more than speculation right now.