Stranger Things Season 5’s Surprising Returning Character After 8 Years Away, Explained

The first volume of Stranger Things 5 marks the beginning of the end, launching the final chapter of The Duffer Brothers’ epic horror saga. As the last season, the new installment carries the immense weight of resolving the series’ most puzzling mysteries, from the true nature of the Upside Down to the harrowing fate of Max Mayfield (Sadie Sink) following the catastrophic events of Season 4. While the new episodes diligently begin to unravel these central questions, they also solve a significant loose thread that many fans may have long forgotten. In a truly unexpected twist, the season brings back a powerful character from the show’s past, reintroducing a key player for the final battle against Vecna (Jamie Campbell Bower).

Warning: Spoilers below for Stranger Things 5, Volume 1

The new season establishes early on that the U.S. military, led by the ruthless Dr. Kay (Linda Hamilton), has built a secret research facility within the Upside Down. Their presence becomes a direct threat when a military patrol, dispatched to investigate the mysterious flesh wall, encounters Eleven (Millie Bobby Brown) and Hopper (David Harbour). The soldiers deploy a potent sonic weapon that incapacitates Eleven with a wave of excruciating psychic pain, a form of “kryptonite” she has never encountered before.

In the ensuing firefight, Hopper manages to destroy the weapon and capture the patrol’s leader, Lieutenant Akers (Alex Breaux). During a tense interrogation, Eleven pries into Akers’ mind, discovering the existence of the secret base and a heavily reinforced door at its heart. Unable to see what lies behind it, but feeling this is the source of the military’s new weapon, Eleven concludes that a being of immense psychic power is being held beyond the door. She becomes convinced the military has captured Vecna and is attempting to weaponize him against her. The reveal drives Eleven and Hopper to undertake a dangerous mission to infiltrate the base, find the secured room, and destroy Vecna once and for all. 

The emotional climax of the infiltration sees Hopper preparing for a suicide mission. Eleven notices he is carrying explosives, a last resort he plans to use to ensure Vecna is destroyed. He says a heartfelt farewell and enters the secured area alone, ready to sacrifice himself to save Elven. Crying at the thought of losing another father, Eleven drags herself to the door. To her surprise, Hopper re-emerges unharmed. He takes her inside the room, where the true source of the military’s power is revealed. It is not Vecna strapped to the machinery. It is Eleven’s long-lost sister from Hawkins Lab, Kali Prasad (Linnea Berthelsen), also known as 008.

Stranger Things Season 5 Brings Back Kali, Eleven’s Sister from Season 2

Kali was first introduced in the divisive Season 2 episode, “The Lost Sister.” As one of the other numbered children from Hawkins Lab, she possesses the unique psychic ability to create convincing illusions and manipulate what people see. When audiences last saw her, she was the leader of a gang of outcasts in Chicago, using her powers to hunt down and exact revenge on the former lab employees who had wronged them. After that single-episode appearance, Kali’s storyline was seemingly abandoned, with subsequent seasons making no mention of her. The devastating revelation in Season 4 that a young Henry Creel had massacred nearly every other test subject in the lab seemed to be the final nail in the coffin, effectively burying the possibility of any other survivors and closing that chapter for good.

The return of Kali in Stranger Things 5 is a shocking move, signaling a commitment from the creators to tie up every remaining narrative thread before the series concludes. Kali is the only known loose end from the Hawkins Lab conspiracy, and her specific skill set is uniquely suited to combat the show’s final villain. One of Vecna’s abilities is to create elaborate mindscapes, trapping his victims in mental prisons. Kali’s power to project illusions could become a strategic countermeasure.

Volume 1 of Stranger Things 5 is currently streaming on Netflix. Volume 2 arrives on December 25th, with the final episode following on December 31st.

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