The CW’s new supernatural drama “Legacies” doesn’t require viewers to watch “The Vampire Diaries,” but those who did tune in will know that the Saltzman twins are in trouble. The witches from their bloodline are cursed, but Lizzie and Josie actresses Jenny Boyd and Kaylee Bryant revealed that fans might have more details than the twins right now.

“They don’t know much,” Bryant, who plays Josie, told International Business Times earlier this month at New York Comic Con when asked how much they know about their biological mother and the Gemini Coven. “But I don’t think we can talk much about that because that’s just — it’s a storyline that we’re exploring throughout the show because it’s a big part of who we are as twins, and it’s something that you’re going to see kind of unfold throughout the series.”

[Potential spoilers ahead.]

Their family history is pretty gruesome. Their biological uncle was a psychopath who killed all of their relatives, and, more importantly, the twins might be destined to fight to the death. “The Vampire Diaries” explained that twins in the Gemini Coven take part in a ritual called “The Merge.” When the twins hit age 22, they’ll fight and the strongest will absorb the other’s power, killing them. It’s not a ritual they can just opt out of, though. If they don’t do it, they’ll die.

Legacies Saltzman twins
"Legacies" will show that Josie (Kaylee Bryant, left) and Lizzie (Jenny Boyd) don't know everything about their family history. The CW/Miller Mobley

It’s pretty obvious why Alaric (Matt Davis) and Caroline (Candice King) would keep that from their kids because no one wants to scare their children. Plus, Caroline is likely searching for an out. Showrunner Julie Plec previously teased that the headmistress is MIA because she is searching for something pertaining to “the long-term survival of their daughters.”

However, when the girls do find out, it’ll break their hearts. In the “Legacies” premiere, which airs Thursday, viewers will learn that Josie and Lizzie, while very different, are extremely tightknit.

“At the beginning, they’re super close,” Boyd told IBT. “They have a strong twin bond. They sleep in the same bed.”

Alaric (Matt Davis) hasn't told daughters Lizzie (Jenny Boyd, center) and Josie (Kaylee Bryant) everything yet on "Legacies." The CW/Miller Mobley

“And I think that’s always going to be something,” Bryant added. “They are always going to have a strong bond together. It’s the outside things that affect that, and it’s just how we react to that. I think we’re always going to be there for each other no matter what. I hope so.”

Outside factors aren’t their only challenges. Boyd’s Lizzie is also handling her mental illness. “I did a little research on bipolar disorder,” she explained. “It’s a sensitive subject, and I wanted to bring the truthfulness of that to her. I think, as well, being young, her emotions are very overwhelming. And I think everyone can identify with that, to have very, very strong emotions.”

Meet the twins when “Legacies” premieres Thursday at 9 p.m. EDT on The CW.