When the Justice League isn't capable of battling supernatural and magical threats, Justice League Dark is born. A live-action movie adaptation of the comic book series with the same name is being made as part of DC Extended Universe expansion plans.
The official announcement was made at the 2017 San Diego Comic-Con, along with other DC films to be added in the Extended Universe, namely Suicide Squad 2, The Batman, Shazam, The Flash, Wonder Woman 2, Green Lantern and Batgirl.
The movie has been in the works for quite some time, with Guillermo del Toro originally hired to be the director. At the 2013 WonderCon he expressed his hopes to be able to start with the screenplay soon with the story already planned out. The plot revolves around the origin of the group with John Constantine recruiting Swamp Thing, Etrigan the Demon, Deadman, Spectre, and Zatanna to join him in his quest.
In May that year, the script was said to feature Madame Xanadu along with Constantine, Swamp Thing, Deadman, and Zatanna, with The Floronic Man as the main antagonist. In June 2015 del Toro pulled out of the film with Scott Rudin taking over in October of the same year.
In August 2016 Doug Liman was named the new director of the film to be made but he also stepped down from the project in May 2017. The director cited conflict in schedule as the reason behind his decision, as he would be working on two other films, Chaos Walking and the Edge of Tomorrow sequel, instead. More recent news suggests the director and other people involved did not see eye to eye where the script was concerned.
As of this writing, Gerard Johnstone has been reported to polish the script but no director has been announced to take over the project yet.