The 'Dune: Prophecy' premiere ends with a shocking twist. Star Jihae breaks down Kasha's fate.

• The series premiere of "Dune: Prophecy," which aired Sunday, ended with a shocking twist.
• The HBO show is a prequel series set within the universe of Denis Villeneuve's "Dune" movies.
• The star at the center of the twist spoke to BI about filming her character's big scene.

Warning: Major spoilers ahead for "Dune: Prophecy" season 1, episode 1.

A pair of shocking deaths close out the first episode of "Dune: Prophecy," the new HBO series that serves as a prequel to Denis Villeneuve's "Dune" movies.

The show, set 10,000 years before the birth of Paul Atreides (Timothee Chalamet's character in the films, who was first played by Kyle MacLachlan in David Lynch's original 1984 version of "Dune"), centers on the origins of the Bene Gesserit.

The group that would become the Bene Gesserit of the "Dune" films was originally a powerful, mysterious sisterhood, headed by Valya Harkonnen (Emily Watson in the present day, and Jessica Barden in flashbacks). They wield political and social force to shape the future of the Imperium behind the scenes, orchestrating royal marriage matches to breed an ideal ruler. Some members also possess superhuman abilities, like mind control, attained through mental and physical conditioning.

One member of the sisterhood is Reverend Mother Kasha, played by South Korean singer and actor Jihae in the present day scenes and "Bridgerton" season four lead Yerin Ha in the flashback sequences. When we first meet her in episode one, Kasha is serving as the Truthsayer (a specially trained sister capable of detecting falsehoods who's assigned to royal houses) to Emperor Javicco Corrino (Mark Strong).

While her loyalties are truly to the sisterhood and their shared mission, Kasha formed a special bond with Corrino's daughter, Princess Ynez, whom she'd known and cared for since childhood.

Kasha is rattled when she has a shocking vision about Ynez in the premiere, and flees back to the sisterhood's home planet Wallach IX, where she tries to convince Valya and Tula Harkonnen that danger is coming.

But despite Valya's dismisiveness, that danger comes by the episode's end.

Kasha wakes screaming in the night and is found burning to death from the inside out. Kasha's death leads Valya to conclude that she's witnessing the beginning of the catastrophic event that her predecessor, Reverend Mother Raquella Berto-Anirul, warned about on her death bed.

Below, Jihae breaks down her big scene, how she got in the headspace to burn to death, and how a personal tragedy made filming the moment even more intense.

Did you know Kasha would die by the end of the first episode?

Yes, I did.

Did you have any trepidation about taking on a character who wouldn't be around very long?

Not at the time. No, the way the script went along, it was such a rich journey for her.

A lot changed since I accepted that role in 2022; it was a two-year situation. But I have to say that, as difficult as it was, it was such a huge learning lesson for me.

Can you elaborate on that?

Well, it was difficult. It's never easy to play a role where you are going through severe, intense physical pain, and to portray that in a realistic way without hurting yourself. I think we're so used to watching violence and violent things that happen in shows, that it just seems like, oh, it's just another thing.

There's a thousand ways for an actor to learn how to act, but there's nothing out there that tells you how to take off the character, how to take off that emotion. So yeah, it was tough. It was tough coming out. It was tough going through it. But we choose these challenges so we can grow, and I definitely grew from it.

How did you mentally prepare to get into that headspace to portray that kind of pain?

I don't believe in using my own stuff. I don't believe in Method acting. I think that is really cruel to oneself, especially in these types of scenes. And I don't know how Method acting is viable at all when you are doing physically violent things in the scenes, at all.

So, here's what I did: Women have gone through so much pain historically — we go through double the amount of pain that men do. But also in terms of having our rights, how much women had to suffer for suffrage and for just basic rights, to own a home, to have a credit card.

I decided to take this opportunity to be a portal through which all the ancestors before me, female ancestors, who had something to say, but weren't able to say it, who had all this angst because of all that they suffered — I decided I will allow them to scream through me. So it made it that much easier to be realistic, because it's based on truth, it's based on experience. That actually did make it easier for me.

In terms of aftercare, how did you come down from that?

Luckily, Budapest is full of hot springs, and I love going to those places and just letting it all go.

The first round of filming, it was end of 2022. My dad had just passed away, and so it was even more intense dealing with all that. I think I was able to just do the deed, the number of days it took, and then just had a wonderful, wonderful holiday.

How many days were you filming that scene?

It was three to four days. My body just started revolting. When I got the news that they're adding a day, my body was just shaking. It's like, no more.

Was the death the last thing you shot?

That was the first thing I shot.

More was added later. I actually requested, could I please be at my powerful first when she first appears, and then she did that scene.

But there was no chance of accommodating any of that, just because I had to be absent for five months due to the strike.

When you signed on back in 2022, what was your familiarity with the "Dune" universe?

I loved the movie. I decided to get the book, and then I learned that it was inspired by the book, but not taken from the book. So I decided to go and research more about Frank Herbert, and what his intentions were with the books.

I was lucky enough to spend some quality time with someone who knew Frank Herbert, and had insight in what Spice was about, how he came up with it. Paul Stamets, who's a mushroom scientist, is a friend, and he told me in the '80s they had this long walk, and Frank told him that his whole concept of the Spice came from a mushroom trip.

Older Kasha is obviously no longer, but will we see your version of Kasha again at any point in the season? Or is it all just Yerin Ha's Kasha from here on out?

That's a mystery to me, because I've only seen one episode.

Did you and Yerin share any notes to coordinate your interpretations of Kasha?

Oh, we did. We sat down with the showrunner and the executive producer, and so it was the four of us discussing how we should sound like each other and be like each other.

"Dune: Prophecy" is very female focused and headed by a female showrunner too. What was that energy like on set? Was it different in any particular way from other sets you'd been on?

No, I don't know if it's any different, really. But I do have to say that I have a lot of respect for any showrunner, because it's so much work. And I mean the amount of things you have to say yes or no to, and the things that you're on top of. But I have a lot of respect for Alison [Schapker]. We've worked together before on "Altered Carbon."

It's a miracle that anything gets made — just the amount of people you have to rely on for something to come to fruition. And in the world of COVID, when somebody gets sick, we have to stop. It's wild. It's a wild thing that these things actually get done.

I absolutely adored the collaborative energy of the women involved in this project. It's really wonderful.

This interview has been condensed and edited for length and clarity.

"Dune: Prophecy" airs Sundays at 9 p.m. ET on HBO and is streaming on Max.