Source: Entertainment Weekly

Much has been made about Barb’s kind-of-return in the Stranger Things final season (i.e. her charred remains), but the first four episodes of season 5 came with a livelier surprise comeback.

After battling her way through the Upside Down with Hopper (David Harbour), Eleven (Millie Bobby Brown) finally busts down the reinforced door inside Dr. Kay’s (Linda Hamilton) lab to see what Brenner’s replacement kept locked away all this time. The answer, which came at the end of episode 4, “Sorcerer,” is Kali.

Linnea Berthelsen returns as Eight, a.k.a. Eleven’s psychic “sister,” for the very first time since her three-episode arc back in season 2.

“When Netflix [and series creators] Matt and Ross Duffer reached out about coming back as Kali, I was so intrigued to see where they wanted to take her,” Berthelsen tells Entertainment Weekly via email. “I care about her so deeply, and making sure she’d be in great hands was important to me.”

Fans will recall that Kali was one of the many psychic children kept in Brenner’s laboratory in Hawkins alongside Eleven. She has the unique ability of projecting illusions and warping peoples’ minds to see what isn’t there. Kali eventually broke out of the lab and sought revenge.

The last time we saw Kali (not including memories) was is season 2, episode 7, “The Lost Sister,” when she and her crew drove away from gunfire from the cops chasing them. Eleven chose to go back to her family instead of staying with her to avenge her mother.

“I was amazed by their raw, quite ambitious vision for Kali in season 5 of Stranger Things, and excited that the season would be directed by the brothers, [series executive producer] Shawn Levy, and the brilliant Frank Darabont, whose work I deeply admire,” Bethelsen continues. “Because we discover Kali under such different circumstances in this season, the cliffhanger reveal at the end of episode 4 didn’t actually feel like I was stepping back into character, but instead it felt like a first reveal of the brothers’ vision for her in this season and an insight into who I personally believe Kali has always been underneath her various personas.”

In a separate interview with EW, the Duffer Brothers dig into why they brought the character back after all these years. “None of it would play out the way it would if she wasn’t involved again,” Matt says of the season 5 story.

“That was hard, to keep Linnea under wraps for a full year of shooting,” Ross adds. “So kudos to security and production and Linnea herself. She’s outside, she’s filming. It was a lot of work to keep this under wraps.”

According to the brothers, it was always going to be Kali behind that locked door. They list out the far more unlikely scenarios. “Everyone else is dead,” Matt says. “Eddie was never gonna turn into a vampire.”

“Barb’s gone,” Ross adds, after which Matt comments, “That would’ve been shocking, though.”

Matt describes Kali as “this loose end that we had never really resolved,” noting, “We’ve talked about bringing her back before, but there was not a narrative or thematic reason to bring her back. She’d served her purpose in season 2, but it still felt like this loose end where Eleven just left her there. What happened to her?”

Once the Duffers assembled the season 5 writers’ room, they realized, “to really tell this story completely, we needed to bring her back,” Matt continues. “As you’ll see in Volume 2, she’s really there. Her reason for being there is very important in terms of Eleven’s journey and also the journey for this story to end.”

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