Constantine hasn't even premiered, but plans are already in motion for establishing a mystical DC Universe within the show.
In an interview with ScreenRant, Constantine's showrunner and writer David Goyer discussed other DC Comics characters that might appear on the NBC series. While Goyer stressed that any larger plans are contingent on the show's success and renewal, he did outline a rather detailed picture for a "Dark" DC Universe.
When asked if fans could expect some iteration of The Justice League Dark, the occult-based League that Constantine belongs to in the comics, Goyer said "yes."
"…Even within the first 12 episodes we've introduced two or three characters from the broader DC universe that are not just exclusively from Hellblazer. Corrigan has been mentioned, but there's a couple of other characters we haven't talked about that will show up as well," Goyer told the website. "If the show takes off and we get our back nine and come back a second season, we sort of have access to that whole corner of the occult universe."
For those not in the know, Jim Corrigan is a DC Comics character with ties to its cosmic spirit of vengeance, the Spectre. In his original version, Corrigan is a murdered police detective who hosts The Spectre. However, a revised version of the character also appeared in the "Gotham Central" series as a crooked cop who murders a different host for the Spectre. Either way, Corrigan's presence opens the doors to DC's other supernatural regions.
A much more exciting possibility, however, is the inclusion of Swamp Thing. Goyer said, "The idea has been thrown around," but would only give the character serious consideration after Constantine makes it through its first season. And if Goyer were to include the character, he would only do it in a way that did him justice. "We don't want a cheesy version of Swamp Thing," he told ScreenRant. The two characters share a deep history at DC Comics. John Constantine made his debut wtihin the pages of Swamp Thing in "The Saga of the Swamp Thing #37" in 1985.
Constantine—and the rest of the supernatural DC Universe—hits the air when Constantine debuts on October 24th on NBC.