A Guide to All the Stranger Things Villains and Antagonists

Stranger Things season 4 will premiere on May 27, 2022. The Netflix original science fiction horror series follows the super-powered protagonist Eleven and her teenage friends from Hawkins, Indiana. Steeped in mystery, intrigue, and brimming with monsters, the show is beloved by audiences everywhere for its melding of scary stories and coming-of-age drama.

Season 4 is releasing in two volumes. With this split, we’re expecting the show to wrap up threats from both the Upside Down and the outside world. But what exactly are all these threats? With three seasons of antagonists, it can be difficult to keep track of all the danger. So, we’re breaking down the major Stranger Things villains — plus we’re reminding you where we left them and wondering how they might appear in the final season.

Martin Brenner

Martin Brenner was the director of Hawkins National Laboratory. As a senior research scientist, Martin led the controversial experiment Project MKUltra. Project MKUltra was a covert CIA study with the express goal of creating humans with mind-control abilities. The subjects were meant to be used as weapons during the Cold War.

During the trials, subjects were tortured, beaten, starved, and given psychedelic drugs. One subject, Terry, was pregnant at the time and subsequently gave birth to a girl named Jane. Jane had psychokinetic abilities due to the experiments performed upon her mother. Even after Project MKUltra was shut down, Brenner continued to experiment on Jane — calling her Eleven, as the eleventh subject in a new experiment. Brenner also raised Eleven to call him “Papa” and develop a toxic type of filial loyalty for him.

In the show, Brenner was last seen in his lab. He was attacked by a monster from the Upside Down, with his fate unknown. However, it’s looking like “Papa” will be back for a final round of mental and physical torture in season 4 — even if it’s just flashbacks.

The Demogorgon

Named after the creature from Dungeons & Dragons, the Demogorgon first appeared in Eleven’s mind during sensory deprivation experiments. Unbeknownst to Eleven, she was crossing over into the Upside Down, or a parallel dimension. The predatory humanoid monster was able to access the Gate between dimensions once it contacted Eleven, and thus it was unleashed upon Hawkins in Stranger Things season 1.

The Demogorgon, also known as The Monster, could travel between dimensions at will by creating temporary portals in each realm. It kidnapped victims from Hawkins and brought them to the Upside Down to consume later or to feed to unidentified eggs. Besides being a formidable opponent in combat with its super strength and telekinesis, it was exceedingly difficult to kill. Not even burning it worked because it had the ability to regenerate. Eventually, however, Eleven was able to disintegrate the Demogorgon with her psychokinetic powers. It has not appeared again since its death.


D’Artagnan, affectionally referred to as “Dart,” was named after a protagonist from The Three Musketeers. Dustin Henderson found Dart in a garbage bin on Halloween. Because the creature was small and defenseless, Dustin took it home to raise as a pet. While he kept Dart a secret for awhile, he eventually told his friends. They wanted to kill it. Dustin insisted it was harmless.

Dart was never, in fact, harmless. The hidden and actual secondary antagonist of season 2, Dart was the same species as the deceased Demogorgon. It grew into adolescence remarkably quickly and then terrorized the group as the fearsome Demodog. Ultimately Dart died alongside the other Demodogs when the Gate closed.

The Mind Flayer

Alongside Martin Brenner, the Mind Flayer / Shadow Monster was the second overarching primary antagonist of the entire series. The malevolent Mind Flayer ruled the Upside Down. But he got hungry. Utilizing various destructive abilities, the Mind Flayer attempted to take over Hawkins and even the world. His powers included control of the Demogorgon, tendrils (vines that could cross from the Upside Down to a parallel realm), and a group of mind-controlled people known as the Flayed.

In Stranger Things season 2, the Mind Flayer took over Will Byers’ mind and body. Fortunately, Eleven closed the Gate between dimensions, thus severing the connection. In season 3 the Gate was reopened by a military group attempting to draw from the Upside Down’s resources. In order to return to Hawkins, the Mind Flayer “flayed” humans and rats, melting their bodies with acid and merging them into a physical body sometimes called “the Spider Monster.”

Fortunately, Joyce Byers and Jim Hopper were able to close the Gate and banish the Mind Flayer once more. This was also after excessive explosives were hurled at the Mind Flayer. However, it didn’t seem harmed by these. Thus the Mind Flayer is likely biding its time in the Upside Down. We can only assume it will emerge in season 4 for one last bid against humanity.

Billy Hargrove

Billy Hargrove and his younger stepsister Max Mayfield moved from California to Hawkins, Indiana. The step-siblings’ father physically abused Billy, and the boy grew up to be a bully of a similar caliber. He taunted and tormented Max’s friends constantly. Billy also antagonized Steve Harrington, friend and babysitter of Will Byers and Co., almost beating Steve to death before being injected with a tranquilizer.

So, even without the Upside Down, Billy was dangerous. But in season 4 Billy was infected by the Mind Flayer. Forced to do its bidding, Billy kidnapped Hawkins residents to feed the Mind Flayer and create its giant physical form. Eventually Billy broke free of its control when Max reached his repressed emotions, reminding him of the love he had for his dead mother as well as for his living little sister.

Of course, Billy’s breakthrough was accompanied by a self-sacrificial move. The last we saw him, the Mind Flayer had impaled Billy through most of his vital organs after he rushed to protect Max from its wrath. Unless there’s some supernatural healing happening in the Upside Down, Billy Hargrove is absolutely staying dead for the remainder of Stranger Things.


Grigori was a hitman aligned with the USSR. In Stranger Things season 3 he relentlessly pursued Jim Hopper because Hopper was close to discovering the truth about Starcourt Industries’ secret Upside Down experiments. During one of their encounters, Grigori killed the scientist Alexei and tried to shoot Hopper, but Hopper was wearing a bulletproof vest.

Much to his chagrin, Grigori consistently failed to apprehend his targets. His final confrontation with Hopper occurred in an underground base below Starcourt Mall, where a man-made Gate to the Upside Down had been created. Hopper wounded Grigori before tossing him into the Gate. Such unprotected exposure to the machine ripped Grigori apart, killing him instantly.

However, just because Grigori is gone does not mean his organization is defunct. On the contrary, Starcourt Industries as well as the USSR appear to be main players in Stranger Things season 4. We will also spend some time during the show in Russia so we can expect antagonists related to and similar to Grigori soon.

Who or what is your favorite Stranger Things antagonist? Let us know in the comments, and don’t forget to Let Your Geek Sideshow!