Beth Dutton is not the nurturing type, unless you count grudges. The world has been brutal to her, and she has responded in kind. That’s one reason Kelly Reilly’s cutthroat Yellowstone character is so appealing to fans of the series. She betrays no weakness and is impervious to everything. It only hurts sometimes, when it’s love and happiness ricocheting off her.

That’s why viewers of the modern Montana Western have been obsessing over a scene in the final episode of season four, in which Beth passes through a barn on her family property and is greeted by Carter, a homeless, orphaned kid she brought to the ranch and has been protecting like the child she never had. “Morning, mama,” he says, while cleaning a stall. “Hey, baby…” she replies reflexively. Then she halts, and the dim smile ices over.

“You can’t call me that,” she says. “It’s not true.” There’s no reason she has to rebuff the boy, but she can’t live with that word being applied to her. “You lost your mother, kid. You don’t get another,” she says. “I lost mine. Same goes for me.” The final cut comes as she’s leaving: “Crying doesn’t help.”

She may as well have been speaking to the heartsick viewers who have been yearning for Beth to receive some comfort, love, and compassion. For four seasons, they have watched her battle self-destructive demons while valiantly fighting for her father (Kevin Costner) and their family’s legacy. Carter seemed like a well-earned reward for Beth, and it stung to see her reject him so coldly. Fans have been debating about exactly why she did it ever since: Maybe she was trying to protect him because she knows her life is in danger? Maybe it was just self-defense because she does care for him? Or could they be wrong and she is actually just that mean deep down.

These are all hard possibilities to accept. It’s hard for the woman who plays Beth too. “I mean, I find it heartbreaking. I do,” Reilly says, speaking to Vanity Fair after a day of shooting season five of the series. “I found it very emotional to read that, and I sat with it for a minute.” The infamous “mama” scene may not give the audience what they want, but Reilly feels it is still true to Beth.

“It was absolutely the correct response for this character because let’s just be real for a second. He’s just come into their life. He’s been there for maybe two weeks. She can’t just suddenly go, ‘I’m going to be your mother.’ That wouldn’t be truthful. He’s lost everything. She’s taking him in. She’s cooking for him, she wants to look after him. I think Beth has huge motherly instincts—huge. It’s all over the show, actually, but not in a way that women are supposed to be mothers, right? It’s not softly, softly. This is not Disney.”

“Lots of people want to ask me why isn’t Beth just bringing that boy to her bosom and mothering him,” the British-born actor adds. “Well, what she says to him is actually the most honest thing she can. It’s hard to say it to that beautiful little lip-quivering face of that boy. It was heartbreaking to have to say to him: ‘You lost your mother. You don’t get another.’”

The outpouring of analysis about why it happened may simply be a sign that it hit the audience in a meaningful way. “There’s so many things going on in that moment, which is what makes it beautiful writing. It makes it a pleasure to be able to try and act all those notes,” Reilly adds. “That’s what I love about my job. I get to be able to try and do that. And it pissed a lot of people off. They really wanted Beth to just soften and say, ‘Yes, baby, come here!’ and have a happily ever after, but that’s not Taylor Sheridan and that’s not our world.”

Sheridan, the cocreator, showrunner and writer of nearly every episode of Yellowstone, takes an equally tough-love approach to his loyal viewers. “I don’t have any idea how it was received. I don’t follow any of that stuff,” he says when asked about the fan speculation about the Beth “mama” moment. “I don't do social media. I write these for us. And I think just because an audience wants something, it doesn’t mean the right thing to do is give it to them.”

Many of those theorizing about why Beth would reject the boy’s term of endearment seem to forget how loaded the word “mother” is for her. As a young girl, Beth was blamed—cursed, even—by her dying mother for causing the horse-riding accident that fatally injured her. “She can take on a role that is somewhat similar, but I don’t think Beth thinks of herself as a mother,” Sheridan says. “Her only experience with a mother is her mother and, and her mother was pretty tough.”

Beth has been replacing every part of herself with steel ever since, so anything that might soften that armor must be pushed away. “People are like, why is she so tough? Why is she so mean? And I’m like, well, what are you talking about?” Reilly says. “This is a woman who had to survive so much. How is she going to survive that by being weak-spined, by being gentle? Gentle will kill you. Gentle will bend that flower and take its leaves off it and it will be done. To find that strength isn’t always pretty.”

If keeping Beth true to her roots means holding the audience’s expectations at arm’s length too, then so be it. That may even be why Yellowstone viewers feel so passionately about the show, and love Beth in particular: It’s challenging. It demands rigor. Savagery is one of its dark delicacies, as with Succession and Ozark, but when true bonds of trust and loyalty are forged, it’s also deeply satisfying.

That’s what Beth has with Rip (Cole Hauser) who also came to the Dutton Ranch as a troubled young man, her brother Kayce (Luke Grimes) and their aging pater familias. Sheridan suggests she may also have been holding out on the boy deliberately. “Beth is mistrusting of motives, generally speaking,” Sheridan says. “But she’s extremely affectionate with Rip and with Kayce and her father. Carter hasn’t fully proven himself yet, and it was a pretty rash decision to have this boy live with him. Beth can be extremely impulsive and make a decision at the drop of a hat. But the interesting thing about her is she stands by the decisions. She sticks with it. So, could Carter earn that from her at some point? Yeah, maybe.”

It’s a testament to Beth that viewers crave happiness for her in a show where that outcome seems unlikely for almost anyone else in this tragic story of a family undone by its own power. Viewers are drawn to her even though she is one of the most ferocious figures in the show, cutting a swath of destruction to forge a perimeter around the Dutton’s imperiled land. Maybe she’s appealing because she so rarely unleashes that ruthlessness for herself.

“She cares about other people's happiness more than her own,” Reilly says.

Beth is also relentless. “She refuses to surrender,” Sheridan adds. “I think that that’s one of the reasons so many people are inspired by her. She will not allow herself to be a victim—and stands up for those who have become one.”

“She’s a very liberating character,” Sheridan goes on. “She’s the only character I’ve ever written that can say or do anything, no matter how shocking or offensive or out of place. And she owns the consequences, if there are any…. She’s a ton of fun to write, and Kelly has embraced that. She embodies that recklessness.”

One thing Beth does need for herself is conflict, Reilly says. War is her natural habitat.

“She’s so good at it, that’s all she’s ever known,” the actor says. “Look, they’re not peaceful people. All they’ve known is how to fight. The same with their ancestors who fought for the land. They’re still fighting for it, defending it, and Beth is savage and brilliant. For her to just sit on the porch and contemplate life and read Walt Whitman…I don’t think that's going to happen anytime soon. Maybe there’s a spin-off one day where we see her—me as an old lady—but at the moment, there’s too much to lose.”

That loyalty is at the core of Beth’s appeal, and maybe Yellowstone’s overall success. It’s certainly not the purity and virtue of the main characters that wins people over; it’s that we are brought in close to characters who push others away. “It’s basically the mob now, running Montana,” Reilly jokes.

“These characters can be heightened and heroic even if they’re doing things that are potentially, I don’t want to say evil…” Reilly says. “We’ve watched the mob and we love them. We love The Godfather, right? We love these characters who are taking out the bad guys because we are on their side. We have a glimpse into their world. And I think the Duttons have stepped into a little bit of that heroic gangster role.”

Beth remains their most lethal assassin, demolishing the Duttons’ opponents legally, financially, and sometimes emotionally. This past season, the environmental activist Summer Higgins (Piper Perabo), who was also romantically entangled with Beth’s father, got a taste of her wrath. Beth manipulated her in a way that not only served the Dutton Ranch, but also landed the woman in prison. It’s hard to look at such power plays as strictly business; it’s also personal. “She plays dirty,” Reilly says. “She has one endgame and that is to win. And if there’s someone to get that done, it’s her. At the beginning of season five, which I’m not allowed to talk too much about, she’s actually in her most powerful place.”

Is it difficult to bring a character with so much turmoil to life? “It’s not a walk in the park,” Reilly admits, then quickly adds: “I get energized playing her. She gives me a lot of strength, a lot of backbone that I didn’t know that I necessarily had. She’s gotten me through some things also. Actually, I’m not going to say that. It sounds so wanky, so I’ll leave that bit out.”

It’s not that she puts a lot of herself into Beth. It’s that Beth draws things out. “You think you’re playing something outside of yourself and then you discover, yeah, that element is already in me. I’ve just maybe buried it or don't want to look at it,” Reilly says. “The biggest thing that Beth is made up of is grief, I think. And who doesn’t know what grief is? So I relate to some things in her and understand them and I find the way they’re executed are really truthful and powerful.”

Sheridan said that he likes to have as many scripts as possible ready for the actors at the start of each season so they can see the full arc of what they’re playing. With Beth, he describes a constant collaboration between himself, Reilly, and the hair and makeup artists and costume designers to craft a fearless figure who is constantly trying to destabilize the world around her.

“She looks at a board meeting, or she looks at a negotiation as warfare,” Sheridan says. “She weaponizes herself for those things anywhere that she can gain an advantage. She’ll dress in what one would consider a little risqué for a nightclub to go to a business meeting. She does it to intimidate. She does it to off-put, she does it to challenge—whether it’s a male or a female that she sees across the table from her. Then you’ll notice that when she’s on the ranch, she dresses very differently. She dresses comfortably because she’s at ease and she’s extremely confident.”

One thing Beth will never do is pander for approval. That’s what sets her at odds with her buttoned-up other brother, Jamie (Wes Bentley). “Despite himself, he wants it so bad. He wants success and to be loved so bad,” she says. “And Beth finds that so repulsive.”

Don’t expect Beth to seek the audience’s love either. “She's polarizing and I think they all are,” Reilly says. “In our show, it’s almost like [Sheridan] keeps everyone on their toes a little bit because you can be really behind a character and then they do something that you absolutely hate or find shocking. You get that real conflict with where your loyalties lie.”

Affection for Beth endures because she is aspirational. Even Reilly wishes she was that fearsome.

“To have that inner fight, for right or wrong, for whatever it is, I find that admirable. I find that a character that I want to stand behind, or to have stand with me,” she says. “We can go, ‘Oh, my God, that’s awful what she does. She destroys people. She}s unkind, she’s ruthless,’ but when she’s standing in righteousness, it is the same amount of power. It’s the same amount of big dick energy.”

Reilly rethinks her phrasing. “Maybe you shouldn't use that,” she says, then decides it’s fine. (It certainly sounds like something Beth would say herself.) “Yeah, use it. I don’t mind using it because it’s true…. It’s just a shortcut to try and to express the feeling of someone who inhabits themselves so fully that it’s uncompromising. It’s audacious.”

Just don’t call her “mama.” That’s offensive.

A guide to Hollywood’s biggest races