The heart and soul of Under the Banner of Heaven is a woman named Brenda Wright Lafferty. The real Brenda was raised in Twin Falls, Idaho, an agricultural city about two hours southeast of Boise, known for its spectacular — you guessed it — two falls. Her father had a degree from Cornell and both parents encouraged Brenda to go to college and chase after her own dreams of being a broadcast journalist. But Brenda’s life took a turn when she transferred to Brigham Young University in Utah, where she met and fell in love with Allen Lafferty. The Lafferty clan were a bastion of conservative Mormon ideals in Utah and Brenda — beautiful, ambitious, and outspoken — butted against the family’s ways. Around the time Brenda married Allen, his older brothers were falling under the spell of Fundamentalist Mormon beliefs, which included polygamy and blood atonement.

FX’s Under the Banner of Heaven tells the horrifying story of Brenda’s murder in 1984. Based on Jon Krakauer’s non-fiction book of the same name, Under the Banner of Heaven follows fictional detectives Jeb Pyre (Andrew Garfield) and Bill Taba (Gil Birmingham) as they try to unravel what would possess anyone to kill not only Brenda, but her 15-month-old daughter Erica. It’s a disturbing deep dive into the intersection of Mormon history and contemporary crime, but at the center of it all is the memory of Brenda, played by Daisy Edgar-Jones.

During a recent FX press day, Edgar-Jones told journalists that Under the Banner of Heaven creator Dustin Lance Black had collated an immense amount of research, including primary sources for Brenda.

“I had a lot of access to the letters she had written to her sister and I think something that really struck me was what an incredibly empathetic person she was,” Edgar-Jones said. “I think in the scenes that we see, particularly in that first episode, we watch her watching people quite a lot. And I think that was something I really wanted to capture, that she’s someone who is always kind of more concerned with the experiences of the people around her than what’s going on for herself. And I think that empathetic quality was what I really wanted to try and emulate in my performance.”

Besides capturing Brenda’s “empathetic quality,” the British Edgar-Jones also nails her suburban Idaho accent. (At least, as someone who has family in Idaho, I think so.) In a recent interview with Decider, Edgar-Jones joked that she had to figure out how to get back to her own accent after doing three different American accents in the last year.

“But I think it really does inform a character, even from a physical perspective. I didn’t realize until I started working in accents how the way we speak affects the way we move. It’s really fascinating,” Edgar-Jones said.

“With Brenda she grows up in Idaho, but she’s also wanting to pursue broadcast journalism so I wanted there to be some neutrality to her voice. Because obviously she wants to be a news reader. One thing I wanted to convey was her warmth and I think that’s very present in that accent, and in that voice.”

Brenda is one of the few female characters in Under the Banner of Heaven who is constantly using her voice to advocate for herself and the people she loves. While other Mormon women feel the pressure to acquiesce to the men in their lives, Brenda believes that the Holy Spirit not only speaks to women as well as men, but that her thoughts, dreams, and ideas matter. Nowhere is this more evident than in two scenes in Under the Banner of Heaven Episode 2. In the first, Brenda navigates sexism in her workplace; in the second, within the Lafferty family.

In the former scene, Brenda is trying to convince a misogynistic journalism teacher that she is just as capable of being a newsreader as any of the men in her BYU class. She uses logic to reason with the teacher, and then uses his own lecherous behavior — locking her in the studio with him — to advocate for her own screen time. Brenda’s kindness is her cudgel. Daisy Edgar-Jones told Decider that she loved that scene as soon as she read it.

“I think we really see in that scene that Brenda sort of navigates what’s asked of her in terms of being agreeable and in many ways she is sharply aware of how to use that to her advantage,” Edgar-Jones said. “I think the way she navigates that scene is really interesting. It’s all here and it’s all coming from a really kind place, but she’s really giving it to him.”

“So yeah I think Brenda’s an interesting sort of lens into the Lafferty family, in particular, because her experience with the faith is very different to theirs and the other women. She comes from a liberal family that really wanted her to pursue an education and I guess she doesn’t quite fit the norm in terms of the Lafferty perspective.”

No where is that more evident in the second major scene, where she gives struggling sister-in-law Matilda (Chloe Pirrie) a pep talk. It’s a moment that not only shows how the other Lafferty women look to Brenda for strength and support, but how the Lafferty brothers are extremely threatened by her influence over their wives.

“Matilda is completely out of her depth,” Chloe Pirrie told Decider. “And it’s a real cry for help and she ends up divulging all sorts of things to Brenda in that moment.”

“I think what was really amazing in the playing of it was we really felt the proximity of the men in the family and how much they didn’t want the women to be talking. The fact that we are having a conversation together that’s in depth in that scene when they really want to sort of shut it down. There’s a lot of that in this show right from the beginning. It’s touched on in all the different time periods as well. And that was really rich.”

So much of the darkness permeating Under the Banner of Heaven is the stench of sexism, both in the show’s contemporary scenes and flashbacks to Emma Smith’s (Tyner Rushing) experiences in the early LDS church. Brenda and her daughter died because Brenda would not stay quiet. She would raise her voice for herself and what she thought was right. Brenda’s spirit is what made her dangerous and what made her so extraordinary. (Decider)