We already had a hunch that Guillermo del Toro’s Justice League Dark will not be included in the DC Cinematic Universe – in other words, Swamp Thing, Deadman, Constantine and the others have no chances of meeting Batman, Superman and so on.
Guillermo del Toro:
“I haven’t followed up with Frankenstein so I really have very little to add to that. Right now theonly sort of shared universe project I’m working on is Dark Universe for Warners, you know, for DC, which is Swamp Thing, Demon, Deadman, Zatanna. It’s a very different universe.”
Source: Comic Book Movie