Games Workshop has confirmed that horror specialist Mike Flanagan is developing Amazon's long-awaited Warhammer 40,000 TV series, and that his role goes further than previously known. According to Deadline, Flanagan is in talks to serve as executive producer, showrunner, writer and director, effectively making him the creative lead of the project rather than just a scriptwriter, while the show itself has now been confirmed as a television series rather than a film.

Henry Cavill, who signed on as executive producer and star back in December 2022, remains attached, with Games Workshop CEO Kevin Rountree confirming that Cavill and his production company Vertigo "remain involved as they have been for some time." Flanagan is best known for Netflix horror hits such as The Haunting of Hill House and Midnight Mass, and recently signed a multiyear deal with Amazon MGM Studios, with a Carrie adaptation as his first project there and Warhammer 40,000 likely the second. IGN's Wesley Yin-Poole speculates Cavill's character may draw on Dan Abnett's popular Eisenhorn novels, while cautioning that a full horror tone seems unlikely given the franchise's broader scope.