From show creator Paul Zbyszewski and based on the Marvel comic, the Hulu series Helstrom follows siblings Daimon (Tom Austen) and Ana (Sydney Lemmon) and explores the complicated family dynamic that arises when your father is a mysterious and powerful serial killer and your mother is plagued by a literal demon. While Daimon is a professor of ethics who moonlights as an exorcist, Ana runs a successful auction house but secretly hunts down those who hurt others, at the same time that the estranged brother and sister both wonder just how deep the evil runs in their bloodline.

During the virtual junket for the show, Collider got the opportunity to chat with co-stars Tom Austen and Sydney Lemmon about how little they actually knew about the story they would be telling, trying and failing to correctly guess the twists and turns, how the gruesome and horrific is like catnip for an actor, the challenge of disavowing evil when it’s also a part of you, doing the stunts and effects as practically as possible, and how surprising the ending of the season is.

COLLIDER: These see like such fun characters to play. Did you have any idea of what all of this would become? Did they tell you much of anything initially?

SYDNEY LEMMON: No.

TOM AUSTEN: They told us where to be for the first day.

LEMMON: They said, “The car is coming, just get in.”

AUSTEN: “Just get in and don’t ask any questions.”

When did you realize what the story was that you would be telling and who these characters were?

AUSTEN: About ten minutes ago. No. Obviously, there’s a lot of secrecy that goes on with a Marvel property in the development stage and when they’re meeting actors, so you really find out very little. All of the characters were given code names. What we were told a lot about when we were meeting the producers are the kind of relationships that we were playing. From that, you could go, “Okay, I’ve got some idea of what’s going on. I can figure out my way through the human side of this.” The rest of it was just one surprise after another.

LEMMON: In this Marvel world, there is a huge understanding that we’re not allowed to talk about what’s going on but that was part of the thrill. We would be given a juicy episode and we could sink our teeth into it but we didn’t really know what was around the corner. We could take guesses. Tom and I definitely did spend hours going, “What do you think will happen next? Should we even bother trying to figure out?” The gift of working in that way is that you can just sink your teeth in and stay super present and tell the most of the story that you have on hand. I think it actually ended up being a virtue because, by the end of the season, you’re really just playing through every moment by moment because that’s what you have.

AUSTEN: And we never, ever guessed right, either.

LEMMON: We were never right. They kept us on our toes, for sure.

Before you guys had been cast in these roles, was there ever a point in the process where you became attached to your character and would have been really upset if you’d had to watch somebody else playing the role?

LEMMON: There’s always this thing with acting where my goal for myself is to completely fall in love with it and yearn for it, need it, and want it. But then, as soon as the audition tape is sent or the door slams on the room, I make it vanish as quickly as it came in, so as to preserve my sanity and my mental health. Of course, Ana was very special and I would be lying if I didn’t feel right away like, “Oh my gosh, this fits like a glove. This feels different.” And so, for me, there was a bit of a claim, so I was really happy I didn’t have to feel disappointed in this case because I’ve felt it before.

AUSTEN: As an actor, you read a script or you’ll be meeting for a part and you always feel like you have a notion of what the job is gonna be like and what the experience is gonna be like. If you lose a part, you’re yearning for an experience that is only ever an imagined one. I feel like when you really fall in love with a character is when you actually do it. If you haven’t done it, you’re only missing out on a fantasy, really. We were so extremely lucky on this show that the fantasy came to life and was every bit as great as we had hoped and imagined it would be.

This is definitely a dysfunctional family with a capital D. What was it like to develop that dynamic along with your showrunner, and then balance that vulnerability that they both have, even if they’re trying not to show it?

LEMMON: It was fun. It was so much fun. The more gruesome and horrific and fractured it became, the more fun it was to bring to life. Why is that fun? Who knows? But it is. It’s like catnip for an actor. You want to get in there and make it real and true.

Both of these siblings are hunting down the worst that humanity has to offer. How does what they’re doing in their present help them deal with their past? Is it something that they do because it helps fill something that they couldn’t really deal with before?

AUSTEN: I think they think it helps them. I’m not sure how much it actually helps them at all. The only thing that really can help them is by coming back together and being a family again, and that’s the one thing that is the most unattainable thing. They have these powers and abilities. They can do things to themselves and to other people that are so beyond the realms of anything that a human being could understand but they can’t have that one thing, which is the love of the family, and that’s what they want the most.

As the offspring of a powerful serial killer who was clearly a very bad man, how hard is it for them to disavow evil when that evil is also a part of them?

LEMMON: That’s a great question. That’s something that plagues both of them, for sure. For Ana, she’s born with these abilities and part of her disdains to have them because they remind her exactly of the source from whence they came, which is her dad, who has given her such intense baggage. In that way, she hates that part of herself. What does she do with it? She turns it into her advantage. She seeks out people who do harm like him, and then uses her powers to enact justice where she can. She makes lemonade out of her really sour lemons — or at least tries to.

AUSTEN: What the show is about is good and evil, and how nothing or no one is ever exclusively one or the other. That’s especially true of Daimon and Ana. This thing runs through their blood and is in their veins. What we see in the show is that Daimon and Ana are constantly in this fight between being in control of the evil and the evil being in control of them. We see that the whole way through. For me, that’s really what the show is about.

You have the special effects and stunts that come with doing a Marvel project, you also have all of these gruesome things going on, and you have all of the family drama. Did it feel like you were working on a Marvel project, did it feel like you were doing a horror project, did it feel like a family drama, or did it depend on the day?

LEMMON: That’s a great question, and you put that so beautifully. I think it’s all three.

AUSTEN: Yeah, it’s all three, all the time.

What’s it like to do the stunts that come with their abilities? They’re manipulating energy in different ways, and there are different visuals that come with that. Is there any way to represent that without feeling a bit awkward and silly, even though it looks great in the final product?

LEMMON: Practical magic is happening all the time, so there is a level of suspension of disbelief where you just have to buy in all the way. Things might not happen in full sequence but there’s this understanding that somehow, magically, in the editing room, it will all come together. Anytime that you’re really seeing something, it was usually happening on set. When a person flies across the room, they were being flown with ropes and wires. For Ana, who does a lot of hand-to-hand combat, it was such a joy to learn those fight sequences and to be in there with those people doing those moves. It was so empowering and cool. That stuff wasn’t fake. There was nothing about that that didn’t actually occur. We had incredible stunt performers who were also there helping to supplement all those moves and take the really hard hits and leap off of balconies. We were in there doing those sequences, and that was some of the greatest stuff for me on set, getting to learn how to be a bad-ass, or at least trying to be.

AUSTEN: Nothing makes you feel cooler than standing in front of a ten-foot wall of flames. The fire that you see in the show was there in front of us. If we were standing in a ring of flames, we were standing in a ring of flames. There’s something so cool about tangibly being close to danger. If something goes flying, it goes flying. When we were fighting, we were fighting. We were all on wires. All of this stuff was happening for real. You know that things are gonna be sped up, or they’re gonna add something cool into it afterward in post-production, but so much of it was happening live. You felt like you were creating this thing, but then there’s also a real danger to doing it. I’d be lying if I said I didn’t get a buzz out of that.

Without spoilers, how do you think fans will react to the end of the season and where you leave things with the story and these characters?

LEMMON: I think where the story goes in the second half of the season is the place that people would not have been able to anticipate. I don’t think that they even have to wait until the end of the season to feel gobsmacked. That happens along the way.

AUSTEN: I agree. I feel like the show does a really incredible job of answering big questions that are posted throughout the season, and then also, as all good TV shows do, it asks some new pretty big ones right at the end. I hope people will really like it.

What was your reaction to learning where your characters would end up and where this would leave off? Could you have seen it coming yourselves, or were you surprised?

AUSTEN: I was totally surprised.

LEMMON: I don’t think I ever could have imagined it.

AUSTEN: We were given scripts episode by episode as we were shooting, so we weren’t told a whole arc or journey for our characters at the beginning. Sometimes we’d be doing a scene and we’d be into it, and they’d be like, “Maybe just pull this back a little bit,” or “Maybe give us a little bit more of this.” We wouldn’t necessarily always know why but we’d just have to go with it and trust it. And then, you’d read the next episode and you go, “Right, okay. Now we get why we were doing that.”

Helstrom is available to stream at Hulu.

Christina Radish is a Senior Reporter of Film, TV, and Theme Parks for Collider. You can follow her on Twitter @ChristinaRadish.