I've Got a Theory for Who Henry Cavill Will Play in Amazon's Warhammer 40,000 TV Series

Following Games Workshop’s announcement that horror specialist Mike Flanagan is working on Amazon’s adaptation of Warhammer 40,000, and that the Haunting of Hill House creator would soon be working on a script, we have further news that this project is a TV series — not a movie — and that Flanagan may have an even more significant role than previously thought.

Deadline reports that Flanagan is in talks to join the series as an executive producer, showrunner, writer, and director for the series. So, he’s not just writing the Warhammer 40,000 TV show, he’s creating it.

Where does this leave former Superman actor and Warhammer 40,000 superfan Henry Cavill? Games Workshop CEO Kevin Rountree said that Vertigo and Cavill “remain involved as they have been for some time.”

All the way back in December 2022 (yes, it’s been nearly four years since Games Workshop and Amazon announced their intention to work together), Cavill was said to be “bringing his lore expertise to the mantle of Executive Producer, and his sword arm to the starring role.”

“I have loved Warhammer since I was a boy, making this moment truly special for me. The opportunity to shepherd this cinematic universe from its inception is quite the honour and the responsibility,” Cavill said at the time. “I couldn't be more grateful for all the hard work put in by Vertigo, Amazon and Games Workshop to make this happen. One step closer to making a nigh-on lifelong dream come true.”

So, Cavill is still very much involved, and, as far as we can tell, will be in the leading role. But what does Flanagan’s previous work tell us about what to expect?

Flanagan is writer, director and showrunner of a number of much-loved Netflix horror TV shows, including The Haunting of Hill House, The Haunting of Bly Manor, The Fall of the House of Usher, Midnight Mass, and The Midnight Club. Earlier this year he signed a multiyear deal with Amazon MGM Studios to develop and produce original series for the studio, and the first of these is an adaptation of Stephen King’s horror classic, Carrie. Presumably, Warhammer 40,000 is the second.

That’s a lot of horror, so should we expect a horror-heavy Warhammer 40,000 adaptation? Not necessarily. While there is much about the grimdark far future that is horrific, I do not expect a traditional horror series set in the world of Warhammer 40,000. While there are straight up horror stories in the setting, it is not known for traditional horror.

I also think this Warhammer 40,000 TV show will have to be mindful of staying grounded to a degree, not least to keep it within scope and budget. The Warhammer 40,000 setting is so vast and varied that you have everything from stories about downtrodden humans who scratch about in the lower levels of a Hive world, right up to galaxy-cracking space battles between fleets of voidcraft. Truly, you can do anything in the world of Warhammer 40,000. You can even have metaphorical battles of the mind in space hell.

So what will the show be about? I keep coming back to Eisenhorn. Let me explain. Last year, I reported on interesting comments from celebrated Black Library author Dan Abnett, who is perhaps the most high-profile Warhammer 40,000 writer today and at the heart of the setting’s development. His long list of Warhammer 40,000 books established much of the lore fans know and love, including the wonderful Gaunt's Ghosts and Eisenhorn series, and key entries in the sprawling The Horus Heresy saga.

Eisenhorn is a trilogy of sci-fi crime novels that revolve around inquisitors Gregor Eisenhorn and Gideon Ravenor (Ravenor got his own spinoff series). The gist is they hunt heretics and daemons while fending off the brain-melting powers of Chaos. While the story is set within the Warhammer 40,000 universe, it is more focused and smaller in scope than some of the other, galaxy-spanning 40K stories that involve long-running space battles and thousands of Space Marines fighting alien monstrosities and even each other.

The Eisenhorn saga includes a spinoff series that revolves around an Inquisitorial agent called Alizebeth Bequin. The first novel in the Bequin series, Pariah, came out in 2012. Its sequel, the Warhammer 40,000 lore treasure trove that is Penitent, followed nearly a decade later, in March 2021. The hotly anticipated third novel in the series, Pandaemonium, does not have a release date, and the wait for an announcement is fast becoming Warhammer 40,000’s version of George R. R. Martin’s M.I.A. Game of Thrones book, The Winds of Winter.

Why should so many Warhammer 40,000 lore lovers care so much about Pandaemonium? Because it promises to actually move the overarching plot forward. Penitent ended with a significant lore revelation (it has to do with the identity of the mysterious King in Yellow, which we won’t spoil here), and so the ramifications of Pandaemonium could be huge. Everyone wants to know what happens next, and is badgering Abnett to get on and write the damn book.

Then, last year, a seemingly innocuous Facebook post by Abnett himself promoting his attendance at the Broadside Games Show in the English town of Gillingham, Kent, got Warhammer 40,000 fans talking. It included a warning of sorts:

By the way… my previous posts about this event (and, actually, pretty much anything I post) have resulted in many comments asking for Pandaemonium (Bequin book 3). Positively demanding it. And I’m delighted you’re keen, because so am I. But for those who don’t know, it is not MY decision when Pandaemonium gets finished and published. For reasons an NDA prevents me from discussing, Bequin 3 — and some other things — are held up for a while. It’s coming — and I’ll be delighted to bring it to you — but in the meantime, try to be patient… and maybe try to enjoy the things that I AM writing.

This message was brought to you by peace, love, and shooty-death-kill-in-space. See you Saturday.

So, Abnett is bound by a non-disclosure agreement that prevents him from explaining why Pandaemonium and “some other things” are “held up for a while.” That on its own wouldn’t warrant such attention, but in combination with a reddit post from last year, it certainly does set the cat among the pigeons.

In March 2025, redditor Zigoia described a meeting he had with Abnett at a book signing in a Warhammer store in Maidstone, Kent. Zigoia reported that Abnett told him that the delay for Pandaemonium “is because of the potential lore impact it’s going to have on the setting — and is due to GW wanting to get the lore in the TV show totally settled first. They apparently don’t want to end up having some of the potentially galaxy shaking events of Pandaemonium contradict what they lay out in the show.”

With all this in mind, I think Cavill will play Eisenhorn, from Abnett’s saga of the same name. If the delay to Pandaemonium is due to Games Workshop wanting to get its Amazon ducks in a row so the TV show slots neatly into Warhammer 40,000 canon and veteran fans and newcomers alike aren’t faced with two sets of contradicting lore, you can see why the revelations of Pandaemonium might have to wait for Flanagan’s script.

An Eisenhorn adaptation would, theoretically at least, be tighter in scope than some of the grander Warhammer 40,000 stories, and help keep production manageable. The Eisenhorn Omnibus series does feature Space Marines, but they only make brief and rare appearances. The story focuses heavily on Gregor Eisenhorn and regular humans rather than the giant genetically enhanced warriors.

Well, it’s either that, or Cavill will play the King in Yellow himself.

This thing is still years away, unfortunately, so it may be some time before we get any official word. Cavill, in a recent interview with Esquire, touched on the “complexity” and “trickiness” of adapting the Warhammer 40,000 IP. But, he insisted, he was loving the challenge. Bringing Warhammer to life "is a dream come true," Cavill said, "but it's different from what I've done before, in the sense I haven't had my hand on the tiller of things before. It's wonderful doing that. It is a tricky IP, and a very complex IP, and that's what I love about it. The challenges that come with putting this on the page in a way that is doing justice to that complexity, that trickiness, and that nuance, is a challenge I'm enjoying enormously."

When the Games Workshop / Amazon deal was announced, Cavill issued a statement on Instagram saying he’d been “working away in concept rooms, breaking down approaches to the enormity and magnificence of the Warhammer world."

He added: "Together, we've been sifting through the plethora of incredible characters and poring over old tomes and texts. Our combined efforts have led us to a fantastic place to start our Universe, which has been agreed upon by those up on high at both Amazon and Games Workshop. That starting place shall, for now, remain a secret. Watch this space, though — more to come in time!"

Photo by Max Mumby/Indigo/Getty Images.

Wesley is Director, News at IGN. Find him on Twitter at @wyp100. You can reach Wesley at wesley_yinpoole@ign.com or confidentially at wyp100@proton.me.