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.
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).
Before this scene, we saw Max struggling. We could guess what she was struggling with, but it is not until Vecna takes Billy's form and abuses her with her own self-doubt, grief, and guilt that we know exactly what she's suffering.
After Max Mayfield realised she was being targeted by Vecna, her friends and allies scrambled to find a way to stop Vecna's plans; her older friends Nancy Wheeler and Robin Buckley traveled to Pennhurst Mental Hospital to question the imprisoned Victor Creel, who claimed to have survived an attack by the 'demon' that ...
While restoring Eleven's powers in Stranger Things season 4, Brenner explains that Vecna/Henry does not just kill his victims, he absorbs them and takes on their characteristics. As a result, it appears that Max's consciousness has been absorbed by and resides within Vecna.
She breaks free, momentarily incapacitates Vecna, and runs with the determination to live toward her friends, dodging debris that Vecna throws in her path. Max hurls herself through the portal, awakes from the trance, and is held by Lucas (Caleb McLaughlin).
Tragically, Vecna succeeds in killing Max, though she's shortly resurrected by Eleven (Millie Bobby Brown) — or is she? Vecna doesn't just kill, he consumes his victims, absorbing the essence of their minds and souls. Max, who lies in a coma, might have a pulse, but, as Eleven discovers, her mind is empty.
After serving as bait for Vecna, she becomes his “final sacrifice,” getting her bones broken and losing her vision during a low point.
Turns out, he needs exactly four dead kids, like the four chimes of his signature clock, as they are his necessary sacrifices in order to open enough small gates in Hawkins, so that he can create that earth-shattering gate in the final episode.
In simple words, Vecna needs a total of four gates to take over Hawkins and rule it. Now, you must be thinking, why is Vecna killing people if he can take over the complete Hawkins? Well, in one of the previous episodes, it was revealed that with each person Vecna kills, he creates an opening to the real world.
Vecna holds off Eleven long enough to brutally attack Max in his signature style—she levitates, her eyes go white and bleed, and he snaps her limbs. Eleven regains her strength and pushes Vecna off before he can complete the job, but the damage is already done.
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.
One of the most confusing parts of season 4 of Stranger Things is Eleven being able to revive Max. As far as fans know, Eleven hasn't been able to do this before. It's not clear how she gained the power to revive someone or if she would be able to do it again in the future.
Vecna draws power from sad and angry memories and that is the main reason he targets traumatized teens. Those teens are a well of power just there to be absorbed. This is not just a theory, Vecna himself told Eleven about the power that angry and sad memories hold.
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.
What was Chrissy's Trauma? Chrissy's life appears to be free from flaws on the surface, but in reality, she is struggling terribly to conceal her depression and self-image stemming. She was struggling with these issues, which resulted in her developing an eating disorder due to her mother's verbally abusive comments.
She Doesn't Have a Great Aim
After the Hawkins team develops a plan to defeat Vecna, Nancy is in charge to blow his head up with a shotgun. However, either she didn't have a great aim or she was trying to play it safe because she didn't hit him in the face even once, and that may be the reason why Vecna is still alive.
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.
"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."
Max is powerless to do anything, watching as her stepbrother is taken apart by the Mind Flayer. Although they did not have the best relationship, Max feels defeated and, eventually, became clouded with enormous guilt.
Max's death was used a device to push Murphy toward killing Josh in the series finale. Max didn't need to die to wrap up the story this way. Sure, Murphy needed to have a complicated place to land.
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.
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.
Using past traumas to break down his victims, Vecna brought Nancy to the pool where Barb was killed by the Demogorgon and revealed her mangled corpse. Vecna then taunted Nancy with her own feelings of guilt - that she was responsible for Barb's death and had forgotten about her.