Henry chose to save Eleven because he empathized with her. He saw himself in her and wanted to form a kinship with her so he could remove her from her suffering. Henry saw himself as a savior, but Eleven couldn't stomach the carnage and destruction he'd caused without batting an eye.
He did not want to murder Eleven, though. The Henry who once found power in solidarity had plans for them to work together. Henry made an offer to Eleven to join him in his ominous quest to free mankind of its status quo.
Wishing to help him, Eleven was tricked into ripping the device out with her abilities. Following the device's removal, Creel used his restored abilities to commit a massacre, seemingly killing everyone at the lab besides Eleven and Dr. Brenner.
1979: After Henry's attack, Eleven loses her memory and knowledge of how to summon her strongest powers. Brenner said that the massacre at HNL set Eleven back, shocking her system to the point where she didn't remember how to use her strongest powers or anything about Henry.
Remember also that we have evidence that powers can be inherited -- El inherited her powers from Terri Ives, for example. So it stands to reason that Henry inherited his powers from one of his parents.
Henry spends years trapped in the Upside Down, which changes him into the monster that is now terrorizing Hawkins in the present: Vecna.
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.
Brown is likely right in saying that no one created the Upside Down and that the parallel dimension has always existed. And if the boys' science teacher was right in saying there are “infinite variations” of our world in alternate dimensions, there could even be several versions of the Upside Down out there.
Vecna successfully stole Eleven's powers when controlling the Mind Flayer in Stranger Things' season 3 ending, which finally allowed him to emerge stronger than Eleven and enact his plan to take over Hawkins with the Upside Down.
Sharing more about Eleven's real father Andrew Rich could be a great way to wrap up the story.
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).
Vecna's obsession with time appears to be linked to his hatred of humanity. He views time as a human imposition on the natural world; an attempt to impose order on nature.
At his empire's height, Vecna was betrayed and destroyed by his most trusted lieutenant, a vampire called Kas the Bloody-Handed, using a magical sword that Vecna himself had crafted for him, now known as the Sword of Kas.
Then, as he was falling through the Upside Down, One became the creature Vecna after lightning struck him in such a way that it changed his skin and made him into the monster he is now.
Before coming to the Hawkins National Lab, Venca had a classic villain origin story — he became obsessed with black widows, tortured his family, and brutally killed his mother and sister pinning it on his father.
In episode 7, Vecna is revealed to be Henry Creel (played as a youngster by Raphael Luce), the son of Victor Creel (Robert Englund) and his wife Virginia (Tyner Rushing) shown in the 1950s flashbacks.
We find out in episode 7 that just like how everything in the Upside Down is connected, Vecna is also deeply connected to Hawkins and Eleven. Nancy (who is still in the Upside Down with Steve) ends up under Vecna's control, and she starts seeing visions about Barb's death.
In the series, Eleven is shown moments from her past at Hawkins Laboratory, right up until she manages to banish Vecna into the Upside Down.
Following Eleven's resistance, Vecna sought after Eleven's 'power', which he identified as "a means to open [his] own doors" (gates).
Jamie Campbell Bower plays 001 in Stranger Things 4.
He gets punished with electrocution after telling Eleven that Dr. Brenner lied to her about her mother dying during childbirth.
Oh Il-nam (Korean: 오일남), also referred to as the Host or Player 001, is the main antagonist of the first season of the South Korean Netflix drama Squid Game.
As well as befriending Eleven in order to gain her trust so she would remove his Soteria implant, we learn in the final episode that 001 initially spared El because he wanted her to join him. He viewed her as an ally rather than an enemy because they were "alike".
Eleven Was Taught To Access Her Powers Using Lessons Learned From Vecna. Eleven was raised at Hawkins Lab, one of several children granted powers as a result of Dr. Brenner's twisted experiments.
What does Vecna want with El? In his twisted mind, Vecna believes that he his helping the world by wiping out humans, as a "predator, but for good." When Vecna asks for El to join him, it's because he also sees her as a predator, "better" than humans.
Will Became Connected to Vecna During His Kidnapping in the Upside Down. The assumption has always been that Will survived in the Upside Down on sheer dumb luck before being trapped in those creepy hive mind vines.