'Mayfair Witches' star Alexandra Daddario says she approached her character's 'toxic' demon lover like 'a relationship with the boyfriend you shouldn't go back to'

In "Anne Rice's Mayfair Witches," the actor plays a neurosurgeon who learns she's a descendant of witches and wields a secret, lethal power.

• Warning: Spoilers ahead for season one of "Anne Rice's Mayfair Witches."
• Alexandra Daddario plays the lead in "Anne Rice's Mayfair Witches," which airs on AMC on Sundays.
• Her character's "toxic" lover is like "the boyfriend you shouldn't go back to," she told Insider. 

There are roles that push an actor to explore outside their comfort zone, and there are roles that ask the actor to get downright creative. Starring in "Anne Rice's Mayfair Witches" demanded Alexandra Daddario do both. 

Daddario plays a gifted neurosurgeon whose life is upended when she traces her blood ties back to the Mayfair family in New Orleans.

There, she discovers that not only is she the family heir in a centuries-old line of bonafide witches, but being the heir comes with serious baggage. That includes inheriting an evil spirit named Lasher who bonds with the Mayfair family heir of every generation, demanding their love and devotion in a twisted relationship that defies logic.

If it all sounds slightly convoluted, that's because it is. Rice's penchant for intricate (and at times, tawdry) supernatural dramas typically plumbed the depths of despair and peaks of ecstasy throughout her sprawling novels.  

To identify with her character, Daddario tried to ground everything in her character's journey — no matter how paranormal — in the human experience, which included falling under Lasher's spell. 

"It's this very sort of intense, toxic kind of thing that has a lot of pleasure in it for some reason, so I just tried to relate it to something real," Daddario told Insider at the show's premiere in December. 

She added: "When you have these big complex things like a demon ghost, or sort of stalker, what does that look like? I tried to approach it like it's a relationship with the boyfriend you shouldn't go back to, but you can't help that." 

Daddario, who had never read Rice's work before "Mayfair Witches," also prepared for her role by studying "The Witching Hour," the first novel from Rice's Mayfair Witches saga, and poring over articles and interviews about Rice. 

"I really tried to figure out who she was, what she was trying to say, who these people were, what the story was she was trying to tell, and where it came from," Daddario said. "So I did a lot of that to really dive into who this person was, what her struggles were, and the greater themes about humanity." 

Her character's journey through much of season one means dealing with familial deaths and navigating her new, dysfunctional family in New Orleans. It was an arc that proved taxing for Daddario. 

"The character is going through a lot," she acknowledged. "When you cry all day or — we all shot in New Orleans where it's very hot — when you are going to have a character that's going through all of that, and then you also get home, it's a lot."

But as far-flung as the show's story may be, Daddario contended her character's messiness will have some viewers relating to her. 

"There's something very relatable about a woman who really has a lot of her stuff together but is also a mess," she added. "I've always felt when I'm in that place, you sort of feel, well how is this possible? Am I faking everything? I think it's a really, really relatable story as far as you can be both — together and a mess — at the same time and work through things."