Dr. Brenner raised Jane under the "name" Eleven. Brenner built himself up as a father figure in the mind of Eleven and seventeen other child test subjects, making them refer to him as "Papa".
Martin Brenner (Matthew Modine), the Director at Hawkins Lab who raised a number of test subjects with psychokinetic abilities there - including Eleven - and told them to refer to him as "Papa" for them to see him as a parental figure.
Martin Brenner, aka Papa, in Stranger Things. Dr. Brenner worked for the U.S. government and helped raise several children with psychokinetic abilities, including Millie Bobby Brown's Eleven.
While of course Eleven calls Dr. Brenner "Papa," he isn't actually her real father. Eleven's dad was shared in the book Suspicious Minds by Gwenda Bond. The novel was published in 2019 and is a prequel to Stranger Things.
The crux of this episode takes place at the lab in Nevada, where Eleven (Millie Bobby Brown) learns the true nature of her past and the real intentions of Dr. Martin Brenner (Matthew Modine), the man she once called papa.
Dr. Brenner raised Jane under the "name" Eleven. Brenner built himself up as a father figure in the mind of Eleven and seventeen other child test subjects, making them refer to him as "Papa".
Brenner Care About Eleven? According to Matthew Modine's excellent interview by Vulture, Dr. Brenner (AKA Papa) absolutely did love Eleven. But he absolutely doesn't defend what his character did to Eleven or the rest of the children.
Realizing he had tremendous psychic power, he haunted his family with visions before ultimately killing most of them. His father was framed for the murders and locked away in a mental hospital as a disturbed serial killer. Henry then found himself in the care of Brenner, who decided he wanted more kids like the boy.
We know Eleven was born in 1971, which means her mom got pregnant with her during the tests, sometime in 1970. A 1959 flashback in the mid-season 4 finale reveals a 12-year-old One (Jamie Campbell Bower). That puts One, a.k.a. Vecna, as 24 when Eleven was born.
The final scene of Volume 1 shows a shot of Vecna, and a close up of the 001 tattoo on his arm, confirming that Henry Creel, a.k.a. Number One, became Vecna.
Nearing the end of season 4, Dr. Brenner asks — in a roundabout way — for Eleven's forgiveness while he lay dying. Although Eleven refused to give her “papa” that understanding in his final moments, Matthew explained that forgiveness “is the most powerful thing in the universe.”
So, Dr. Brenner waited for One to get older to make him breed with Terry Ives to create Eleven—to make sure that she was the strongest, and clearly, she is." Yep.
As El is embracing Will, her shock collar unclasps. She turns around and sees Papa, just barely alive, who has released her. He reaches for her and utters his dying words, "Eleven, I want you to know, I'm proud of you. So very proud.
1979. Henry told Eleven that the Soteria in his neck was a tracking device that also 'weakened' him. Wishing to help him, Eleven was tricked into ripping the device out with her abilities.
Brenner being a villainous character continued to unfold as Season 2 revealed more heinous acts that the scientist had committed, including setting up a conspiracy to take Eleven away from her mother at birth and further harming the mother when she attempted to take her daughter back.
Next up, the viewers go on to theorise that One/Vecna is actually Eleven's dad. Yep, told you it was wild. The theory claims that Brenner wanted to create a child with stronger powers, so he waited until One was old enough to become a father.
"I walked up to her [as Vecna] and she burst into tears. She wouldn't look at me and she was visibly just disgusted by the whole thing... After she cried and I made it obvious that she knew it was me, one of the things she said was that, 'I knew it was you when I could smell cigarettes,' because I'm a smoker."
While intending to get his revenge on Eleven and Brenner, Vecna also goes after victims who have dealt with traumatizing experiences in the past (reminiscent of his childhood and his time at the Hawkins lab).
Eleven has a memory during this episode and realizes that 001/Henry Creel (Jamie Campbell Bower) wants her to join him on his evil journey, and she banished him to the Upside Down. 001 then transformed into Vecna, the horrifying Stranger Things villain.
His first victim was Chrissy Cunningham. Vecna targeted Chrissy by using her depression and eating disorder against her in his visions. Chrissy was killed in Eddie Munson's trailer, and the first gate was opened on the ceiling.
Played by Jamie Campbell Bower, each prosthetic was glued to his skin with medical adhesive by prosthetics designer Barrie Gower and his team. For the finishing touch, Vecna was covered in "glossy slime to make him really, really glossy and wet looking," according to Gower.
However, within the red smoke of Vecna's Mind Lair, it wasn't the song itself that saved her, but the memories it conjured up. What broke through to Max was the happy, loving memories of her friends, particularly Lucas and Eleven, and these were what truly allowed her to break free of Vecna's grasp and escape.
There's been debate as to whether or not this scene implies that Eleven created the Upside Down or merely opened the first gate to it. But according to Millie Bobby Brown, the Upside Down existed before El ever meddled with it. “I don't think that she created the Upside Down,” Brown told Variety in June.
Who Created the Upside Down? In the "Stranger Things" timeline, the earliest we see the Upside Down is during Eleven's time in the Hawkins National Laboratory when an experiment guided by Dr. Brenner results in her accidentally opening the gateway between our world and the hellish dimension on the other side.
When Eleven wakes she has a collar around her neck, and it's really unclear what the exact purpose of this particular collar is, but it's pretty safe to assume it dampens her powers to make her easier to control.