Why Henry Cavill & Mike Flanagan’s Sci-Fi Prime Video Series Is Taking So Long

Published Nov 11, 2026, 2:52 PM EST Nick Bythrow is a Lead Writer for ScreenRant. He has been writing for the site since September 2022. He graduated from Hampshire College in 2022, where he triple majored in Journalism, Communications, and Media Studies. When he's not writing about TV and movies for ScreenRant and his blog, Frayed Branches, Nick is penning speculative fiction and poetry on Amazon. He lives outside Boston, Massachusetts. Henry Cavill and Mike Flanagan's Prime Video sci-fi series just got another key update. Cavill has provided an update on him and Flanagan's upcoming adaptation of Warhammer 40,000, revealing why it's taking so long to make. Cavill's Warhammer 40,000 TV show was reported to be in development in December 2022, with the actor set to star in and executive produce the series. The series has been in development ever since, with Flanagan joining the project in July 2026 following a deal he made with Prime Video. However, almost four years later, the show remains in development for the streaming platform. Speaking with Inverse about his forthcoming projects, Cavill opened up about the progress he and Flanagan are making on their Warhammer 40,000 TV series. He explained the core reason behind the series taking so long is that he wants to ensure that it's "absolutely perfect" before it's ready to begin production. He says faithfulness to the source material is key to its development, while praising Flanagan as a fantastic creative partner in bringing the grim sci-fi series to a new medium. Check out what Cavill had to say below: It’s going really well. Obviously near and dear to my heart, Warhammer. So it’s one of those things which I want to make sure is absolutely perfect, and we’re protecting the IP whilst also telling the best story we can possibly tell, which will lead to better stories. Mike Flanagan is an incredible partner. He’s such an enormously talented man. Cavill's update comes weeks after Flanagan revealed Warhammer 40,000 finally has a starting point, with the two creatives having determined the best way to approach the live-action TV series. As Cavill's statement expresses, the series will be the starting point of a shared universe produced under Amazon, which will see the lore of the tabletop game expanded into high-budget productions. But, given the intricacies of the universe and the passion behind it, getting it right is key to its success. It's one of many large projects in the Warhammer 40,000 universe currently in development. Another is the real-time strategy game Total War: Warhammer 40,000, a video game that allows players to control battalions of troops across various planets within the larger lore. There's also forthcoming RPG Warhammer 40,000: Dark Heresy, which arrives January 28, 2027, and a third installment in the universe's highly-popular Space Marine series. There is no shortage of Warhammer 40,000 projects to come. But what makes Cavill and Flanagan's so important is that it will be the first released on a broad TV scale. The pair are developing the world in a way that reflects uncharted, experimental territory for the franchise. Finding a starting point was the most important part, though, meaning development is clearly continuing in a positive direction. And, with Cavill wanting to ensure the franchise's TV debut is as powerful as possible, it makes sense for him and Flanagan to take their time. With the show now having a starting point, though, it seems like there will be more positive news about the Warhammer 40,000 TV show once concrete details are secured. For now, the ambitious project appears to be heading in the right direction, which means good things for when the show finally does premiere on Prime Video.