The show WandaVision is teeming with references to the Marvel Cinematic Universe. There are also tons of comic book related Easter eggs, including a few that seem to be alluding to a major Marvel comics character in the comics so far unseen in the MCU: Mephisto.
The devil-like being seems to be behind some of the most obscure Easter eggs and references in the series so far. Mephisto may or may not be a part of the greater mystery of Westview, but he does have a long, complex history, especially with the Scarlet Witch and Vision.
Based On Mephistopheles
Mephisto was co-created by legendary Marvel writer and editor-in-chief Stan Lee and equally legendary artist John Buscema. They based the character on Mephistopheles, a demon from the legend of Faust.
The character is a surrogate of Hell who more or less plays the same role in the various interpretations of the legend, especially in the historic play Doctor Faustus by Christopher Marlowe and the later play Faust written by the German author Johann Wolfgang von Goethe.
Debuted In The Silver Surfer
Despite his connection to demons and Hell, Mephisto debuted in an unlikely place. He made his first appearance in The Silver Surfer #3 back in December 1968.
From the beginning, Mephisto plays the role of the tempter, offering the Silver Surfer the chance to return to his former life on the planet Zenn-La and his partner, Shalla-Bal. Mephisto would play this same role throughout much of his history in Marvel Comics, toying with the emotions and fears of many Marvel heroes, including Scarlet Witch and Vision.
He Isn't Satan... or Maybe He Is
The greater Marvel Universe is a vast, complex system of various realms and dimensions. Heaven and Hell do exist in the Marvel Universe and Mephisto resides in Hell. He isn't the classical Biblical Satan, necessarily, though it's never really made explicit that he isn't.
Mephisto has posed as Satan in the past, suggesting that there is one, but Satan himself has never been seen. Mephisto goes by many names and aliases in the comics, including other mythological names for the devil, like Lucifer.
Held The Soul Of Doctor Doom's Mother
Doctor Doom is one of the most powerful villains in the Marvel Universe. Among his many feats is going to Hell to free the soul of his mother from Mephisto. Mephisto captured the soul of Cynthia von Doom, Victor's mother, who had cast a spell to summon Mephisto for the purpose of empowering her people.
Many years later. Doctor Doom discovered the truth about his mother and used his own magic to summon Mephisto. He challenged him to a duel over her soul and with the help of Doctor Strange, won her freedom.
Appeared In The Ghost Rider Movie
Mephisto may be appearing in the MCU at some point in the near future, but he's actually appeared on screen before. Mephisto appeared as the villain in the first Ghost Rider, a great cheesy Nicholas Cage movie, played by Peter Fonda.
He appears mostly in human form until the end when his more familiar demon form is revealed.
Radical Redesign
Mephisto's look is fairly well established in the comic books, with his wild hair, yellow eyes, and red cape. It wasn't always static. In Daredevil #266, legendary comics artist John Romita Jr., responsible for epic runs on the X-Men and Spider-Man, redesigned Mephisto into something much more demonic.
His Mephisto was much more of a frog-like creature, hunched on all fours with a long tongue and horns. Later appearances of the character would alternate between this version and the classic style.
One More Day
The classic iteration of Mephisto was present in One More Day. There are a lot of underrated Spider-Man comic book stories that could serve as inspiration for a potential Spider-Man 4, but One More Day is probably not one of them.
In this infamous story, Peter Parker and Mary Jane Watson's marriage is erased from continuity when they trade it to Mephisto for Aunt May's life. Though Mephisto played a familiar role as the tempter in the story, One More Day continues to remain controversial among fans of Spider-Man.
The Vision And The Scarlet Witch
Mephisto played a somewhat inadvertent but nonetheless significant role in the lives of Wanda Maximoff and Vision. Wanda unknowingly used fragments of Mephisto's soul when creating her children, Thomas and William. When she discovers the truth, it leads her down a dark and destructive path.
This event occurs in the 1985 comic book series The Vision and the Scarlet Witch, which has served as an influence on the storyline of WandaVision. Given the tremendous range of Wanda's incredible powers, and all the Mephisto teases, it's possible this scenario could be playing out in the show.
Also Tormented Hawkeye And Mockingbird
Mephisto hasn't limited his torment of the Avengers to just The Vision and Scarlet Witch. Around the same time as the 80s mini-series, he was involved in the lives of another significant Avengers couple: Hawkeye and Mockingbird.
Mockingbird died sacrificing her life to save Hawkeye from Mephisto in the early '90s. Clint Barton then went to Hell to try and get her back. She was ultimately resurrected many years later. Hawkeye is getting his own Disney+ series and Mockingbird is potentially a character who could appear.
Not As Strong As The One Below All
Mephisto is a powerful demonic force in the Marvel Universe, but he is far from the most powerful. He has admitted to not being as powerful as The One Below All. If there is a true devil in the Marvel Universe, The One Below All might be it. This powerful entity is the source of all gamma radiation in Marvel, which gives the Hulk and many others their powers.
He is also the ruler of the lowest layer of Hell. This fascinating character was introduced in the pages of The Immortal Hulk, by writer Al Ewing and artist Joe Bennett, and given the current direction of the comics, could play a role in the upcoming Disney+ She-Hulk series.