The 'curse' begins with the victim having severe headaches, nosebleeds and nightmares regarding any traumatic event in their past.
Vecna puts a curse on his victims by finding people who are dealing with tragedies and negative feelings like low self-esteem. When he has begun his process, his victims feel sick, their noses bleed, they have headaches, and they see things that aren't really there, such as a grandfather clock.
In a fit of rage, Henry used his restored powers to brutally murder the other test subjects and workers, and attempted to do the same to Eleven. However, Eleven stood her ground and ultimately overpowered him, sending him through a gate to the Upside Down; there, he gradually transformed into the being known as Vecna.
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.
While caught in Vecna's grip, a tear in the dark dimension reveals her friends on the other side, desperately trying to save her from Vecna's curse. Of course, it's "Running Up That Hill," blasted into Max's headphones that breaks Vecna's hold on her.
Billy's death at the end of season three made Max feel guilty about herself, negatively affecting everyone close to her, causing Vecna to use that to his advantage when trying to break through Hawkins.
This ultimately destroyed Vecna. Though they're clouded with cataracts, Vecna in Stranger Things has both of his eyes.
(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.
The Duffer Brothers had Vecna planned from the start, which is how they were able to tie his character into earlier seasons. Stranger Things revealed Vecna was also behind the Mind Flayer that appeared in season 2.
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.
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.
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.
He was initially trained by his mother, Mazzel, in the art of magic, before she was executed by the government of Fleeth for practicing witchcraft. Vowing revenge, Vecna eventually assumed a mastery of the dark arts achieved by no mortal before or since.
Ultimately, it is revealed in Stranger Things season 4's finale that the reason why Vecna was killing Hawkins teenagers was to create a massive gate that merges the Right Side Up with the Upside Down - and he specifically needed four bodies to do so.
Stranger Things Star Millie Bobby Brown Cried the First Time She Saw Vecna. One of the side effects of using practical creature effects?
He is terrifying because he has access to secrets and the guilt that accompanies those secrets. Vecna's use of his victims' guilty conscious to terrorize his prey is an obvious tool in his arsenal.
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.
If he couldn't physically leave the Upside Down, Vecna needed to use the Mind Flayer to attack Hawkins. He also needed to figure out how strong Eleven's power had gotten since their last face-off. Through Demogorgons and The Mind Flayer, Vecna began to slowly break down the barriers between the two worlds.
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.
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.
Season 4's main villain Vecna contains a multitude of easter eggs. To start, he has a giant, claw-like left hand. This is a reference to the D&D character Vecna, for whom this Vecna is named; the D&D Vecna has a monstrous hand infused with dark magic.
Music evokes strong memories that are both good and bad, so it makes sense that it could open a doorway out of the oppressive alienation of trauma, despair, and guilt that Max found herself in.
The fight distracts Lucas from holding onto Max, who levitates under Vecna's thrall. And then it happens: her bones break, her eyes bleed, and she collapses, dead. Max is dead for a minute, but Eleven (who has been psychically piggybacking onto her from Nevada) uses her powers to restart Max's heart.
"Vecna really is a creature that has mutated in the last however many couple of decades during his time in the Upside Down," prosthetics designer Barrie Gower said. "This is where he has become more overtaken by the Upside Down world and become pretty much possessed and mutated."
"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."