Danny Elfman spoke with the official DC Comics website about coming up with the themes for Justice League.
I came up with two heroic themes, one which was just an overall Justice League theme and one which was a team theme. I’m using that more when the team is coming together. I also have an “Anti-Hero Theme” as well as a Steppenwolf theme. But then I tried to provide really simple little hooks for Cyborg, Flash and Aquaman, without going too far. There’s a certain point where you just get a mess of themes, and that’s just going to be a nightmare. So, I tried to simplify those characters to just a few notes, so that there’s something recognizable, and I tried to keep my new thematic action more involved around the entire group as a whole, so it didn’t get too fragmented. But it was still quite a huge jigsaw puzzle of how to do that in a way that wasn’t too messy and served the purposed of the film. So yeah, Justice League was really a challenging film, but I like challenges.
With Justice League, they’re really launching this franchise as a unique franchise—it’s their own world. Often when a franchise is relaunched, they start all of the music from scratch. Most of the time, that’s a decision that may not harm the financial success of the franchise, but it definitely takes away from the longevity or durability of a franchise. The franchise that I always come back to again and again is Star Wars. It’s the oldest musical franchise we have and wisely, it’s the one time they’ve decided not to do that when they relaunched it. It was a really smart thing. Fans, when they hear little bits of the John Williams themes, even when they’re in an offshoot like Rogue One, it provides this great historical context that ties everything together in a really satisfying way.