Last the “American Horror Story” audience saw Kathy Bates, she was playing a butcher and colony leader in the “Roanoke” season, but in “Apocalypse,” she is playing a character carrying out mass murder in a different way — through the programming of Michael Langdon (Cody Fern).

“Mead is having a hard time as a military, regimented individual making these whacked choices that are affecting people’s lives. I think it’s affecting her greatly that she has to go and kill these kids,” Bates tells Variety.

Bates’ Miriam Mead started the eighth installment of Ryan Murphy’s horror anthology series seemingly as Venable’s (Sarah Paulson) right-hand woman, in charge of keeping the nuclear holocaust survivors in line in their outpost shelter. But her true identity — and loyalty — was so much more complicated than what appeared at first glance.

“I knew she was a robot; I knew she was faithful to Venable; I knew she worked for the Cooperative. But Mead is being caught between Venable and her duty,” Bates says. “The bible [of Mead] is being written as each episode is being delivered to me.”

Here, Bates talks with Variety about what brought her back to the “American Horror Story” world after sitting out “Cult,” Mead’s connection to Langdon, and if she’d want to return to the Stephen King universe after a deep dive in Ryan Murphy’s version of horror.

What made you want to come back to the “American Horror Story” universe for “Apocalypse”?

Ryan Murphy basically saved my life. When I was sick with cancer years ago and I got a job working with him, he turned my whole life around, and that’s why I want to hang with him. And that’s on a personal level, and on a professional level, he’s the man with the big stick these days — and he comes up with great characters, and [the] key is he loves women: he loves older women, younger women, and to find parts for older women, I can’t say enough about that. That’s why I’m there. It’s a home where I can continue to grow and evolve as an actor. … When my show “Disjointed” was canceled, he got in touch with me and said, “Come back.” The reason I came back was because of Ryan Murphy and because he’s given me so many opportunities to play so many characters I never would have dreamed of playing. When he invited me to come back for this season I was thrilled. … Ryan tells stories that are always more than just the story he’s telling, that’s the best way I can say it.

What excites you about the story under the story in “Apocalypse”?

Really, it’s war. … In the very beginning, Venable talks about, “We use candlelight; technology was what destroyed the world.” But in fact, Langdon is all about technology — he has the computer, he’s connected to this powerful Cooperative. … It’s a battle between ways of life. It’s a tribal war, it’s a religious war, and it continues after the war of all wars — the mother of all wars. You think that’s going to be the end, but this becomes the end. We decimated everything, and now these groups are jockeying to recreate the world in the way they want. … I believe the series is about that — about tribes, about arresting power from one another in order to create a world that they feel should be lived in. And of course the natural world and the technological world couldn’t be more opposed to one another. The theme, I believe, is about tribal warfare and the destruction of the world at the cost of staying true to our tribes.

What is the biggest challenge you’re finding this season?

You don’t have as much time as you would like once you get to the set — you don’t have as much rehearsal time. And I like a lot of rehearsal time. A lot of this is coming fully prepared and then discovering things in front of the camera, and I find that difficult, for me, because I like to find time to discover things and then make the choice of what to play.

When did you learn Mead was a robot?

I learned early on that that’s what she was going to be, but they also told me that she’s not robotic. … I didn’t want her to be stiff and unemotional, so we talked all about that. When I went through and I studied the script, I made a list of about a gazillion questions about her. And then I [went] and I talked to Tim Minear, who’s our producer and is the keeper of the flame here and [said], “OK why is she this way?” And, “why does she do that?” And, “does it mean she doesn’t have a soul?” [That way] I can make sense of all of these things in my own mind as I’m playing something.

Mead didn’t know just how bonded she was to Langdon at the start of the season. How did you and Cody work together to find the chemistry of their relationship?

Cody and I, because we didn’t know each other, just started talking. I’ve lost a lot of weight, and I had in my jewelry collection a lot of funky rings that are almost like men’s rings — like a skull ring and stuff like that — that didn’t fit anymore, and I was cleaning things out, and I happened to notice Cody was wearing a really cool ring. I asked him if he liked rings, and he said, “I love rings.” So I said, “I’m going to bring you some rings.” There weren’t many, but I thought he could make them work better than I could. And then he gave me a beautiful book of William Blake with all of these beautiful paintings and he wrote in it, “To a kindred spirit” because we had been talking a lot about acting and training and preparing. We really talk a lot about feelings of the craft and developed a kind of understanding as artists. … We both thought that it was sexual, that [last] scene [between them in episode 3] — that it was a seduction. I have a gun, he takes it away from me, he’s the one that’s running everything and has to finally wake Mead up. She’s had scales on her eyes, as well, just like the witches did — everyone’s had things hidden from them.

How does the entrance of the “Coven” trio challenge Mead and Langdon?

I think it’s very clearly established in [the third] episode that he has opened Mead’s eyes and that she is now bound to him. … The fact that Mallory has now discovered these powers has taken him aback. He thought they were all dead [but] she sees his real face, and that starts to set up the opposition. And then the witches come and they wake their sisters up, so you can definitely assume there’s going to be conflict between the witches and [them].

You’re also a key part of the Stephen King universe and Hulu has renewed “Castle Rock.” Would you ever want to play in that arena, or are you getting your fill of horror anthology with Ryan?

My cup runneth over with Ryan, but I love to work. At the end of the day I’m a working stiff, and I start each character from scratch or phase one or whatever you want to call it. Years ago someone said to me, “I can’t tell you what to do, you won an Academy Award.” And I said, “Yeah, but not for this part!” It’s a wonderful challenge to go and play crazy parts, different parts, and really see “Can I do this?” I don’t care where you are in your career, age-wise, success-wise, wherever, every actor that has really given their all to this profession, that’s what they’re after: to try to create this other person that is not us. And I don’t know why we want to do that — [maybe] we’re overgrown kids and we want to play dress-up, and this is the most amazing dress-up. … I love Stephen King, and I’m sure if they wanted me to do something it would be fun. I love his world, too.

“American Horror Story: Apocalypse” airs Wednesdays at 10 p.m. on FX.