Stranger Things star reacts to "devastating" reveal and "tough" Eleven scene in volume 2

*Warning: Major spoilers ahead for Stranger Things season 5 volume 2.*

With Kali's return in Stranger Things season 5 has come a devastating storyline and a chilling reveal that the terrors that haunted her and Eleven's nightmares as children are not over yet.

After she's rescued from Dr Kay's lab by Eleven (Millie Bobby Brown) and Hopper (David Harbour), Kali (Linnea Berthelsen) recounts the horrors she saw there – Kay keeping countless pregnant women captive and infusing them with Kali's blood in an attempt to restart Dr Brenner's programme.

Kali then realises she has to tell Eleven all of this, and ask something impossible of her – to sacrifice herself along with Kali so that the cycle can finally end.

Breaking down that devastating moment, actress Berthelsen exclusively told RadioTimes.com: "I think there is a part of [Kali] that's just realised what happened to her, like the given circumstances of that character in particular, what she's going through, and being brought back to this place and everything that she has tried to avoid for so many years.

"The other thing is like, how do you explain this to Eleven? How do you convey all of this, knowing that her circumstances are so different from hers? She's devastated. She's falling apart, I think.

"And then there is this very deep love for Eleven at the same time and asking her to do something that's quite tough. It's just a really difficult conversation."

At the end of volume 2, Eleven is left reeling from that conversation, and forced to grapple with what to do for the best, with the finale presumably set to show her decision and its aftermath.

Kali was first introduced to fans in season 2, with viewers left stunned at her surprise return in season 5.

But now, Berthelsen is relishing getting to delve deeper into Kali's character, adding: "Every time you get to develop a character and do a bit more work...it's just such a human place, like it's a very vulnerable place that she's in.

"It's very rare, I think, that you get to work on a character like that, and take a character from what I believe is a persona into something that's quite raw."

It was this development of Kali's character that the show's creators, the Duffer Brothers, first pitched to her when they asked her to come back.

"We had a great conversation about what they wanted to do," she recalled. "And I thought it was quite exciting and different, just the way they took the character in a different direction."

Stranger Things season 5 concludes on New Year's Day.

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