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. He offers her his path as a sort of freedom, as they reshaped the world in their image.
All those years ago, he felt a connection to Eleven because of their shared abilities and the pain that they had both endured at the hands of Dr. Brenner. But much to his disappointment, Eleven rejected him and his visions for the future.
Vecna is a dark mirror of Eleven herself, sharing all her powers, and potentially others as well. A series of flashbacks revealed Vecna was originally Henry Creel, a boy who grew up possessing strange psychic powers.
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 was revealed to be the creator of the Upside Down, and he has some truly dangerous revenge plans against Hawkins and Eleven (Millie Bobby Brown).
There are still a few details we don't know, but it's clear that Brenner secretly kept Henry around as an orderly and the chip in his neck was some kind of power suppressant. Without it, Henry is able to unleash his powers on those in the lab, slaughtering nearly everyone, including the children.
Brenner was able to make or alter the other children so that they would also have powers. Because of that, Vecna was inherently more powerful because he had his powers longer and knew the ins and outs of his abilities.
Hawkins has suffered a lot of trauma over the years - not all of which is connected to Hawkins Lab and the Upside Down - and Vecna's curse takes advantage of that. Vecna appears to carefully choose people who feel a strong sense of guilt or shame, particularly if those emotions are repressed.
(All of which have been cited by show creators the Duffer brothers as inspirations for the villain.) But he does have a surprising weakness: music.
School newspaper reporter Fred Benson (Logan Riley Bruner) fled from a deadly car accident that continues to haunt him. Patrick was targeted due to his father's abuse of him. Finally, Vecna targets Max for her trauma from witnessing Billy's death and uses Barb's (Shannon Purser) death as a way to use Nancy.
Yeah, Bower says Brown was crying real tears during that scene. “She was terrified and freaked out. And Caleb [Heymann], our DP, was very smart and saw that she was having this reaction in the beginning of rehearsal and decided to shoot her first. It's so pure and beautiful,” Bower said.
In the final episode of Stranger Things 4 Volume 1, it's revealed that Vecna isn't native to the Upside Down, but was banished there by Eleven after he gruesomely massacred the Hawkins National Lab.
"Vecna seems to be actually intrigued by Nancy being able to figure him out, to be able to get this close to the truth... I think this is more Vecna's narcissistic traits that pull him to Nancy, why he wants to give her this information."
Netflix Vecna has plans for world domination. Essentially, Vecna hates humanity, and wants to take over their world. He had hoped that Eleven would help him achieve this goal. But when he realised she wouldn't, Vecna instead used her.
What is the significance of 4 for Vecna? The new season shows that the four chimes of the grandfather clock symbolize the four victims Vecna needs to claim in order to enter our dimension and take over humanity.
Stranger Things Deaths by Vecna
Vecna seeks four victims in total. His first three victims — Chrissy Cunningham, Patrick McKinney, and Fred Benson — are all peers of The Party, people they know from school, which makes Vecna's terror all the more real.
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.
After learning how Victor Creel was able to evade death back in 1959, Robin and Nancy deduce that playing the victim's favorite song can help them escape the trance that Vecna places them in, with music and happy memories being the only way to keep Vecna's fatal curse at bay.
Curiously, he also seems obsessed with time, projecting strange visions into his victims' minds—including of the grandfather clock from his home in the Creel House. Vecna's obsession with time appears to be linked to his hatred of humanity.
Once he takes control of the mind, he traumatizes them by showing the visions of their dark past. He takes them to unknown places and gives them a glimpse of himself. The pain of his victims doesn't end here. Every single one of his victims experiences nose bleeding and severe headaches as well.
It seems that the reason why Vecna wasn't killing for the seven years after the Hawkins Lab massacre was because he was waiting to become more powerful as the Mind Flayer and Demogorgons took more victims, as he was likely weakened after being thrown into the dimension.
One Steals Eleven's Powers
Just as Henry could see into the minds of others, from the Upside Down Vecna can still see into people. The vines of the dark dimension, which have made their way to the real world, connect directly into his body.
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.
Eleven demonstrated the ability to overpower Vecna when she piggybacked into Max's memory and again after Vecna took her hostage in the Upside Down. Eleven was the one who first opened the gate to the Upside Down, a skill at which Vecna was less adept.