This article contains spoilers for Stranger Things season 4 volume 1.
Stranger Things season 4 volume 1 introduces Vecna, a terrifying new villain who is killing Hawkins teenagers. Every season of Stranger Things features another monster, but the show has switched things up for season 4; rather than a mindless creature like the Demogorgon or a monstrous intelligence like the Mind-Flayer, it features a powerful human being who has been living in the Upside Down. Named "Vecna" by the Hawkins kids, this being makes its presence felt in the real world through horrific visions that they liken to a curse.
The truth about Vecna is finally revealed in Stranger Things season 4, episode 7. A series of flashbacks reveal the monstrous being is in fact Number One, Dr. Brenner's first subject at Hawkins Lab. Number One possesses all Eleven's powers, but was successfully restrained by Brenner for years; he manipulated Eleven into freeing him, committing a massacre at Hawkins that only came to an end when Eleven herself confronted him. Their battle was the real inciting incident of Stranger Things, with Eleven triumphing - but tearing open a window through the dimensions, blasting Number One into the Upside Down.
Vecna has become one with the Upside Down's hive mind. Although the Hawkins kids believe he now serves as the Mind-Flayer's "five-star general," it's actually unclear whether that is indeed the case; the Mind-Flayer itself is notably absent from the Upside Down's skyline in Stranger Things season 4, meaning it's entirely possible Vecna has supplanted its place as ruler of the hive mind. Whatever the case may be, Vecna's curse appears formidable - and the key to Stranger Things season 4's plot.
Vecna's Curse Explained
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. He then begins to stalk his victims, projecting visions into their minds - sometimes of Vecna's strange, otherworldly grandfather clock, but mostly of people who they believe they have wronged. These visions build over time, and within a space of 24 hours Vecna's victims enter one final trance. There, Vecna taunts them, rejoicing in their heartache and sorrow, before killing them. Vecna's victims die in an agonizing way, lifted high into the air. Their every joint is twisted out of shape by Vecna's telekinesis, making for a horrific spectacle.
Vecna's connection with the minds of his victims is telepathic in nature, and it seems as though he can only kill them when they are completely immersed in the vision. The Hawkins kids manage to save Max - interrupting a vision that began with her guilt and shame over the death of her step-brother Billy in season 3 - by playing her favorite tune. They rightly deduce that music connects with the brain on a deep level, disrupting Vecna's hold and providing a way of escape.
How Vecna Is Opening Gates To The Upside Down
Vecna clearly revels in the pain and suffering he is causing - but that seems to actually be a side-effect of the process, rather than its core component. The Hawkins kids learn that every one of Vecna's killings has torn open a Gate to the Upside Down, potentially allowing creatures from that dangerous realm to make their way into their town. This makes a degree of sense in terms of the overall Stranger Things lore, because it's long been clear a mental contact across the dimensions is key to opening Gates to the Upside Down. Stranger Things season 1 suggested Eleven created the first Gate when she touched the Demogorgon during an astral projection, although that has now been retconned; still, the basic principle seems to apply. Presumably, the Gate is only created when Vecna's victim is fully immersed in his vision, explaining why there aren't countless Gates scattered across Hawkins as a result of Vecna's gentlest psychic touch.
It's interesting to note Vecna appears to draw upon the life energy of the entire Upside Down hive while projecting himself across the dimensions; his actions cause powerful flares of energy that are detectable even from Hawkins. It's reasonable to assume the final act consumes the most energy, with Vecna drawing his victim into an immersive reality, killing them, and tearing open the Gate. The Upside Down hive mind may well be sacrificing great chunks of itself to open these Gates.
Vecna's Plan Explained: Is He Working With The Mind Flayer?
The Hawkins kids assume Vecna is working for the Mind-Flayer, who has long coveted this dimensional plane. But when four of the Hawkins group - Steve, Robin, Eddie, and Nancy - were in the Upside Down, they didn't see any sign of the Mind-Flayer. What's more, Vecna's methods seem at odds with the Mind-Flayer's objectives. In the past, the Mind-Flayer has taken advantage of any Gates to launch direct invasions on Hawkins; now there are three Gates, but there is no hint of an invasion. It's quite possible Vecna has taken over the hive mind, commanding it himself, and is working out his own dark plan. Consequently, this may put him in direct conflict with one of Stranger Things' other monsters.
Surprisingly, when the four were in the Upside Down they experienced a number of earthquakes. These have not been seen before in the Upside Down, and they were not mirrored at Hawkins, which means they could well be significant. One disturbing potential explanation is that these represent a degree of dimensional instability; that every time Vecna opens a new Gate between Hawkins and the Upside Down, he moves the two dimensions closer together, with the aim of merging them. Vecna views humanity as a toxin on Earth, and he would no doubt be delighted to do anything he could to wipe out the entire human race. If that is indeed the case, then Stranger Things season 4 volume 1 really is setting up a potential endgame for the show - a war between the worlds. With such stakes in play, defeating Vecna once and for all is more crucial than ever.