"Gotham" alum Crystal Reed was cast in September as Abby Arcane in the Louisiana-set, supernatural drama.
Deadline.com said the show is slated to debut in 2019.
No other casting has been announced yet.
James Wan, Mark Verheiden, Gary Dauberman and Michael Clear -- the team behind the horror hits "The Conjuring," "It" and "Annabelle" -- are adapting the comic-book property for the new DC Universe digital subscription service, which is the home of "Titans."
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