See Who Joins for the Final Chapter

Linda Hamilton as Dr. Kay

Hamilton told The Hollywood Reporter that she got the call about playing Dr. Kay just “two weeks” after she brought up the idea of retiring — “not because there isn’t enough to do, but just I’m tired of being tough,” she explained .

The Terminator star said her agent got a call about the Netflix hit, asking if she was “available from June to June” and immediately said yes. “He didn’t even ask me.”

While she’s “thrilled” to have joined the series, which she was a big fan of beforehand, Hamilton said that joining the cast, ironically, “ruined the show for me.”

“It’s kind of like imposter syndrome where I don’t [feel that I] fit in there,” she told Us Weekly. “When you really buy into something, you don’t see yourself in it.”

Dr. Kay is a military scientist hunting down Eleven. She makes her debut in the premiere episode, “Chapter One; The Crawl.”

Dr. Kay’s first scene shows her dissecting a creature from the Upside Down that doesn’t bite “but does strangle.” She’s annoyed by a sergeant who tells her they failed to capture Eleven.

“Please tell your commander that I am running into a wall here,” she tells the sergeant. “People are dying, innocent people. I need the girl.”

She makes a more dramatic appearance in episode 4.

Nell Fisher as Holly Wheeler

While Holly Wheeler has been a character in past seasons’ of Stranger Things, she is thrown head-first into the drama in season 5. The little sister to Mike and Nancy was recast with 14-year-old Fisher and appears right after the opening credits of episode 1.

She’s the first target that viewers see of the monster, Vecna, who’s terrorizing the town of Hawkins. She’s transfixed by a figure visiting and waving to her from afar. He stops outside her home, then visits her again outside the playground of her school. Her mother and teacher are worried about the “mystery friend” she keeps claiming to see. She says he’s “protecting” her against “monsters in Hawkins.”

Jake Connelly as Derek Turnbow

Hamilton told The Hollywood Reporter that she got the call about playing Dr. Kay just “two weeks” after she brought up the idea of retiring — “not because there isn’t enough to do, but just I’m tired of being tough,” she explained .

After Vecna takes Holly to the Upside Down, Derek falls under the group’s protection when Will (Noah Schnapp) is able to use his lingering connection to the hive mind to determine that Derek is Vecna’s next target.

The 13-year-old actor was cast in season 5 in July 2024, and wrote in an Instagram post at the time that he was “so excited and honored to be in Hawkins and to join the awesome cast.”

When filming wrapped in December, Connolly reflected on the year he spent filming in Atlanta in another post. “So sad closing my trailer door for the last time, but the memories and friendships I made will last forever. Thank you to the most amazing cast and crew for all of their guidance and support.”

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Alex Breaux as Lt. Robert Akers

Breaux is new to the Stranger Things cast, but he’s experienced in the world, having played Dr. Brenner in Stranger Things: The First Shadow on Broadway.

In the series, Breaux plays Lt. Robert Akers, one of Dr. Kay’s henchmen in the Upside Down, who is working to hunt down Eleven. In Vol. 1, he’s taken hostage by Eleven and Hopper (David Harbour) in the Upside Down and Eleven is able to get inside his mind to learn more about Dr. Kay and the lab she’s running.

Breaux teased to TV Insider that working with Hamilton was “amazing” as he shared how the action star differs onscreen and off.

“She’s so hardcore on camera and tough as nails, and then offstage, she’s like the softest, gooiest person, and gives everyone the warmest hug,” he said. “So it was fun to see her just flip the switch from sweetheart to bad b—-.”