If you haven't seen it for yourself yet, DC Entertainment and Warner Bros. sometimes like to use one division of their company as testing ground for another. The DC Universe Animated features are a regular staple for fans everywhere, and in the last decade or so, DC has taken note of the massive success of its animated branch, and tried to let that help inform their live-action decisions.
The clearest example of this was with the release of the Batman: Assault on Arkham in 2014. That animated featured used Batman's name as a back door into delivering fans an adult-themed Suicide Squad story. Anyone who saw Assault on Arkham could easily see how fan response to aspects of that movie fed into the conception of Suicide Squad.
Same goes for elements of the Justice League animated features that DC has introduced in the last few years. From a more turbulent origin and role for Aquaman (Throne of Atlantis), to the elements of the New 52 comics adapted for the screen (Justice League: War), it's clear that what worked in the animated universe is being ported over to the DCEU films.
The Justice League Dark animated feature trailer debuted today, and fans are talking. We here at Comicbook.com got a look at some extended Justice League Dark footage while at New York Comic-Con 2016, and we can definitely say that the DNA for the Dark Universe movie from DC Films (basically the DCEU version of JL Dark) is possibly floating around in there.
JLD is confirmed Rated-R, and it's with good reason: the film has very "horror" elements, and the mouth on John Constantine alone is worthy of a mature rating. It's also like a Sam Raimi film in the sense that there's a lot of comedy on top of the horror and violence, with even the severed head of a demon getting in a joke or two. All in all: Justice League Dark seems to playing with melding the superhero formula (comedy, action) with horror elements (frights, gross-out moments) in a manner that can later be refined into Dark Universe. The filmmakers will all say they're following their own unique visions... but just watch. You'll see the progression.
As for characters: since Justice League Dark is set within a now-serialized DC animated movie universe, it also establishes connections with the Justice League, via Batman, who is used as the skeptic/comedic foil backboard for all the supernatural happenings. It wouldn't be surprising if Ben Affleck's Batman wasn't used the same way for Dark Universe.
JLD also brings back Constantine TV actor (and massive fan-favorite) Matt Ryan to voice the animated character. Ryan was such a hit at NYCC that it would be crazy to pull him in for Dark Universe; but since fans ever get that lucky, having in the animated universe is nice, too. Beyond Constantine, it's not hard to imagine JLD pulling in characters like Deadman, Zatana, The Demon and Swamp Thing, just to see the buzz they generate with fans. For comparison: Harley Quinn, Deadshot, and Boomerang were all standouts of Assault on Arkham, and made the jump to Suicide Squad afterwards.
Justice League Dark is worth keeping an eye on just as a DC Animated movie experience - but savvy fans should keep note of what they like, and what they don't. Those reactions could help shape the Dark Universe movie we get.
Justice League Dark is expected to hit DVD, Blu-ray, and Digital HD in early 2017.