There is current thinking online amongst fans that Superman may return evil in the Justice League movie, perhaps under the control of Steppenwolf or even Darkseid.
Now potential evidence it could happen comes from composer Danny Elfman who talks with Billboard about his time scoring Justice League in London with Joss Whedon.
Danny Elfman lets it be known he took a very dark take on the John Williams classic Superman score from the Richard Donner movies:
I also had two minutes where I had the pleasure of saying, “Let’s do John Williams’ Superman.” and that for me was heaven, because now I have a melody to twist, and I’m using it in an actually very dark way, in a dark moment. It’s the kind of thing that some fans will notice. Some won’t.
Danny Elfman even goes so far as to state:
It’s a moment where we’re really not sure whose side he’s on.
It’s also thought Superman comes back with a beard and in a black suit, so maybe it’s all starting to fit?
Regarding returning to the John Williams music score, Elfman says:
The people at DC are starting to understand we’ve got these iconic bits from our past and that’s part of us, that’s part of our heritage — we shouldn’t run away from that. Contemporary thinking is, every time they reboot something, you have to start completely from scratch — which, of course, audiences will tell us again and again, is bullsh-t. Because the single-most surviving and loved theme in the world is Star Wars, which they had the good sense to not dump for the reboots. And every time it comes back, the audience goes crazy.
Danny Elfman also confirms he used Hans Zimmer’s Wonder Woman score from Batman v Superman for Justice League and small themes for Aquaman, The Flash and Cyborg.
I created very simple motifs. There are so many themes, you can’t just do a big theme for everything. So i created a motif for Flash, for Aquaman and Cyborg — but they’re very simple things.
Justice League has a November 17, 2017 release directed by Zack Snyder, with the story by Chris Terrio and Zack Snyder, the screenplay by Chris Terrio and Joss Whedon, and stars Ben Affleck as Batman, Henry Cavill as Superman, Gal Gadot as Wonder Woman, Jason Momoa as Aquaman, Ezra Miller as The Flash, Ray Fisher as Cyborg, J.K. Simmons as Commissioner Gordon and Willem Dafoe an Atlantean, Nuidis Vulko.
Fueled by his restored faith in humanity and inspired by Superman’s selfless act, Bruce Wayne enlists the help of his newfound ally, Diana Prince, to face an even greater enemy. Together, Batman and Wonder Woman work quickly to find and recruit a team of metahumans to stand against this newly awakened threat. But despite the formation of this unprecedented league of heroes—Batman, Wonder Woman, Aquaman, Cyborg and The Flash—it may already be too late to save the planet from an assault of catastrophic proportions.