The sudden cancellation of Swamp Thing has left a number of stories unresolved. This includes both future storylines within the show (which had its first three seasons mapped out) and spinoff series focused on members of the supporting cast.
Swamp Thing was cancelled after only one episode had aired, before the show had time to build an audience. Yet fan response to the first episode online was largely positive - particularly among horror aficionados - including readers of DC's original Swamp Thing comics and fans of horror filmmakers James Wan and Len Wiseman, who were involved in the series' production. The show was also a critical hit, earning a 92% fresh rating with professional critics on Rotten Tomatoes.
What makes Swamp Thing's cancellation after having its episode order cut short especially tragic is that it is clear the series' showrunners had big plans. Indeed, Swamp Thing's ending confirms that their plans stretched far beyond a single show and might've led to a shared universe that could've rivaled The CW's Arrowverse. Here's a rundown of every short-changed storyline and spinoff in Swamp Thing that could've led to future DC adaptations.
Floronic Man
Originally an enemy of Ray Palmer's Atom in the comics, Dr. Jason Woodrue was a brilliant but twisted botanist, who used his knowledge of horticulture for evil as Plant Master. Later, Woodrue transformed himself into a half-plant monstrosity with the power to control the flora around him and took up the name of the Floronic Man. Swamp Thing introduced its own version of Woodrue, who had come to Marais, Louisiana hoping he might find a miracle cure for his wife's Alzheimer's in the wetlands. Despite this new background, Woodrue (as played by Kevin Durand) was hardly a sympathetic figure, as his behavior was odd and anti-social and he frequently left his wife unattended to focus on his work.
This came back to haunt Woodrue in Swamp Thing's penultimate episode, as he returned home with the cure he sought only to find his wife in a catatonic state after she overdosed on her medication, apparently unable to remember if she had taken it or not. The Swamp Thing series finale saw a frenzied Woodrue preparing his miracle cure, made from organs he had harvested from Swamp Thing's body. The concoction made Woodrue pass out when he tested it on himself, but when he regained consciousness he spoke of feeling the same sense of connection to the plants around him that Swamp Thing had told him about while Woodrue was dissecting him alive. The final post-credits scene of the finale revealed that Woodrue had been transformed into a plant-man much like Swamp Thing and that he had single-handedly destroyed the local sheriff's office.
It's clear that Swamp Thing's showrunners had big plans for the Floronic Man, as they hardly would've bothered putting together the intricate costume and make-up design necessary to bring the character to life for a single scene. It's possible that Woodrue was intended to be the chief villain of the final three episodes of Swamp Thing season 1, before the episode order was slashed. Something similar happened with the first season of DC Universe's Titans, which was originally planned to end with a big battle against the demon Trigon but was instead reworked into the Titans season 2 premiere. It's also possible (but less likely) that Woodrue might've been intended to be the main villain for Swamp Thing season 2 and that the post-credits scene had always been meant to end Swamp Thing's first season.
Blue Devil
The owner of Marais' one video store, Dan Cassidy was a stuntman and stage actor who seemingly couldn't let go of his past and his one major film role as the superhero Blue Devil. The truth was that Cassidy couldn't free himself from his past and that a poorly worded wish had bound him to the town of Marais until such time as he saved a special woman in need. By the series finale of Swamp Thing, Cassidy had realized his destiny and that he had not bargained for a mere film role. He had, like his character in the movie, become bound to a demonic costume and gained the ability to use a devil's fire on the side of the angels.
Swamp Thing's take on Blue Devil has more in common with Jack Kirby's The Demon Etrigan than the original Blue Devil character from the comics. Whereas the comic book Dan Cassidy was transformed by demonic magic into a literal blue devil with no ability to become human, Swamp Thing's Blue Devil is a separate entity, who Cassidy transforms into. The Blue Devil also apparently speaks to Cassidy and shows him visions of people in need of help. It's these visions that prompt Cassidy to leave Marais in the Swamp Thing series finale and would likely have led to a spin0ff series focused on his adventures.
Justice League Dark
Dan Cassidy was set on the road to heroism by a man he had thought was a studio executive. This man later informed Cassidy that Abby Arcane was in danger and that only he might save her from an untimely death. The same man also had a hand in introducing Swamp Thing to the mysteries of The Green and sent him to confront the rising darkness within the wetlands of Marais. This man was later identified as the classic DC Comics character The Phantom Stranger and the showrunners of Swamp Thing confirmed they had planned for him to bring more supernatural characters from the comics into play, eventually forming Justice League Dark.
It's unknown precisely what other characters this Justice League Dark series might have included beyond the fortune teller and sorceress Madame Xanadu, who was portrayed in Swamp Thing season 1 by Jeryl Prescott. One possibility is that the team might have included John Constantine, the con artist and warlock who briefly had his own series on NBC. Such an appearance alongside Swamp Thing would have been fitting, given that Constantine started out as a supporting character in the Swamp Thing comics. While such a team-up was never confirmed, actors Derek Mears and Matt Ryan both voiced support for the idea online, and Swamp Thing fans continue to hope, however unlikely it may be, that they may yet see such a team-up - perhaps as part of the upcoming Crisis On Infinite Earths event.