Darkseid was originally intended to be in Justice League, according to Snyder’s posts over the years, but was cut out of the final version of the film. After the Snyder Cut was announced as an HBO Max exclusive in May, rumors started up that Darkseid would be in the Snyder Cut version.
The Snyder Cut, and the fandom surrounding it, has a long history. Snyder originally stepped away from Justice League following the death of his daughter, leading Warner Bros. to bring in director Joss Whedon (who was already helping with script rewrites at an earlier stage) to oversee reshoots and shepherd the film through editing and post-production. Once Justice League was released in November 2017, fans took issue with Whedon’s lighter, more comedic contributions to the film. A campaign started not long after the film’s initial release for Warner Bros. to deliver a “Snyder cut.”