Vecna, born as Henry Creel and later revealed as 001/Peter Ballard, is a fictional character and the antagonist of the Netflix television series Stranger Things created by the Duffer Brothers.

Portrayed by Jamie Campbell Bower and Raphael Luce, the character made his debut in the fourth season as a malevolent being from the Upside Down that haunts his victims with horrifying visions of their past traumas before killing them in a sadistic, brutal manner.

As the fourth season progresses, he is ultimately revealed to be the ruler of the Upside Down as well as the mastermind behind all of the events of the series that have terrorized the town of Hawkins, beginning with the disappearance of Will Byers.

After moving with his family to Hawkins, Henry discovered that he possessed telepathic powers and used them to kill his mother and sister, which caused him to fall into a coma.

However, after he revealed his true nature as a misanthropic, nihilistic, and genocidal psychopath, Eleven succeeded in overpowering Henry and sent him through the Hellscape, an unstable interdimensional barrier, where he was gradually disfigured by its abnormal lightning and toxic atmosphere, triggering his transformation into the being known as Vecna, before ending up in Dimension X.

As Vecna, he eventually used his powers in order to control the monsters and became the ruler of the Upside Down, serving as the general and hive mind to all the creatures of the dimension.

Sharing the same name, Vecna is loosely based on the Dungeons & Dragons character much like the other antagonists of the series including the Demogorgons and Mind Flayer.

[6] This was with the intention of creating a meaner, darker, and more menacing villain for the show, having the ability to traumatize its victims before killing them in a horrifying way by breaking their bones and gouging their eyes out.

The suit was designed with "anemic" skin whose integration with the toxic environment of the Upside Down was apparent through the inclusion of "lot of roots and vines and very organic shapes and fibrous muscle tissue."

After numerous failures to keep Henry under control, Brenner ultimately removed him from the group, placed a chip on his neck that suppressed his powers, and replicated his abilities in other children.

Dustin Henderson and Eddie Munson who is accused of being the culprit of the murders, bestow him with the alias "Vecna" based on his similarities with the character of the same name from Dungeons & Dragons.

Eleven, aware of his return, enters Max's mind and confronts Vecna, who is revealed to be the mastermind behind the Upside Down's previous attacks on Hawkins, dating back to 1983 when Will Byers disappeared.

From his traumatic childhood as Henry Creel to the abusive experiments he went through as One and finally to his role as the Mind Flayer’s top general, Vecna is the perfect villain to pit against Eleven.

"[11] Vulture's Devon Ivie wrote, "[Bower] has the distinction of embodying three characters, each more unsettling than the last, as the episodes unfurl: a friendly Hawkins Laboratory orderly; Henry Creel, aka "One"; and the most significant villain of the series thus far, Vecna.

West End Best Friend’s Jack Francis said "McCartney is both chilling and endearing as Henry Creel, whose work is nothing short of intense and visceral, adding a layer of tragedy to this previously simple monster story".

[14] Variety’s David Benedict said, "A shuddering, terrified nerd whose monster creates havoc without and horror within…is due in no small part to the way he holds focus even in the midst of one coup-de-theatre after another".