Billy (Joe Locke) unlocks his true powers in Agatha All Along Season 1 Episode 5 “Darkest Hour/Wake Thy Power” (2024), Marvel Entertainment / Wiccan takes on Doctor Doom in Avengers: The Children’s Crusade Vol. 1 #4 (2010), Marvel Comics. Words by Allan Heinberg, art by Jim Cheung, Mark Morales, John Livesay, Dave Meikis, Justin Ponsor, and Cory Petit.
As practically every fan of the founding Young Avenger member has at this point discovered, when the Marvel Cinematic Universe’s version of Billy Maximoff made his post-WandaVision return in Agatha All Along, he did so with an origin story that deviated significantly from that of his comic book counterpart.

And according to series showrunner Jac Schaeffer, this change was made, simply put, because she personally had “no patience” for the hero’s source material history.
Billy (Joe Locke) realizes he can hear the thoughts of others in Agatha All Along Season 1 Episode 6 “Familiar by Thy Side” (2024), Marvel Entertainment
In the most obvious reveal of all time, in the sixth episode of Agatha All Along, it is revealed that the young man accompanying the series’ titular witch, as played by Joe Locke and heretofore known vaguely as ‘The Teen’, was actually none other than the magic-wielding half of the Scarlet Witch’s magically-conjured twin boys, Billy Maximoff.

His existence short-lived thanks to Wanda undoing her Westview Hex at the end of WandaVision, at the exact moment the Avengers’ magic fades and her children eventually dissipate into the ether, another young man by the name of William Kaplan and his parents suffer a violent car accident, with the family slamming into a tree after being run off the road by an oncoming vehicle.

‘William’ (Joe Locke) returns from the dead in Agatha All Along Season 1 Episode 6 “Familiar by Thy Side” (2024), Marvel Entertainment
Barely clinging on to life following the crash, William ultimately succumbs to his injuries and his heart stops beating before his parents can find help – and upon William taking his last breath, Billy’s wayward soul, desperately scrambling for an anchor to reality, makes its way into the boy’s body.

From there, ‘William’ suddenly shoots back to life, randomly (at least in his perspective) shouting out the name ‘Tommy’ as he does.

Walking away from the accident with said name burned into his brain and a new ability to magically hear other people’s thoughts, William proceeds to seek out Agatha for help in understanding his new existence, in doing so eventually learning his true origins and setting down the road towards truly adopting his Wiccan super hero identity.
Billy (Joe Locke) seeks answers from Agatha (Kathryn Hahn) in Agatha All Along Season 1 Episode 6 “Familiar by Thy Side” (2024), Marvel Entertainment
Of course, as comic book readers may have surely already noted, the MCU’s version of Billy’s origin story plays out much differently than how did it in print.

Way back in far-off year of 1986, after years navigating their tumultuous romance and taking on supervillains side-by-side, the second Vision and the Scarlet Witch miniseries, as penned by Steve Englehart, concluded with the two Avengers defying the odds of Vision’s non-biological existence and giving birth to a set of healthy twin boys, who they proceed to name Billy and Tommy.
Wanda and Vision welcome Tommy and Billy to their family in Vision and the Scarlet Witch Vol. 2 #12 “Double Sized Climax!” (1986), Marvel Comics. Words by Steve Englehart, art by Richard Howell, Frank Springer, Petra Scotese, and Bill Oakley.
Sadly, the quartet’s time together as a happy family would be short-lived, as shortly afterwards in Avengers West Coast Vol. 1 #52, Wanda’s mentor, Agatha Harkness herself, finds herself questioning now only how a mutant woman and a syntehzoid man could conceive children, but also why, when Wanda isn’t paying attention to them directly, the two boys seem to blink out of reality all together.

But before anyone can even begin to investigate the issue, the supervillain known as Master Pandemonium reveals himself to the happy couple to reveal that not only were their children not real, having been conjured by Wanda out of thin air by using her hex magic to manipulate two pieces of the villain’s soul (which he had previously sold to Mephisto in exchange for power, thus rendering the boys as actually part of Mephisto’s soul, but that’s a whole other story), but also that he was planning to reabsorb them into himself in order to become whole.

Following a battle between the West Coast Avengers and Master Pandemonium for the souls of Billy and Tommy, Mephisto himself eventually materializes onto the battlefield to, in classic ‘trickster devil’ fashion, render the entire emotional ordeal null and void by simply reabsorbing the boys into his own existence and then simply returning to Hell.
Master Pandemonium prepares to strike in Avengers West Coast Vol. 1 #51 “I Sing of Arms and Heroes” (1989), Marvel Comics. Words by John Byrne, art by John Byrne, Mike Machlan, Bob Sharen, and Bill Oakley.
However, like in the MCU, this ‘erasure from reality’ was not the end for the twins.

In attempting to deal with and heal from the loss of her sons, Wanda’s grief eventually leads her to blame the Avengers for the tragedy, Unfortunately, seeing an opportunity to both protect his sister, Pietro proceeds to manipulate her mind and convince her that the only way for her to stay safe was to rewrite the world in her father’s Magneto’s image.

And thus, the House of M universe was born.

Eventually, after a siege upon the Castle Magento and an all-out brawl between those who remembered reality as it was and those under the sway of the illusion, Wanda eventually snaps back to her senses, in doing so not only restoring the world to its original form, but also significantly crippling its mutant population.
Scarlet Witch changes the world in House of M Vol 1 #1 (2005), Marvel Comics. Words by Brian Michael Bendis, Art by Olivier Coipel, Tim Townsend, and Frank D’Armata.
And unbeknownst to anyone, while the world dealt with the now-remaining 198 mutants and the Avengers began to navigate the burgeoning Skrull invasion, two families were welcoming the newest additions to their families – Billy for the Kaplans in New York and Tommy for the Shepherds in New Jersey.

Roughly fifteen years later, the boys would discover that they each possessed their own set of super powers, with Billy having an affinity for magic manipulation and Tommy finding himself as one of the 616’s few true speedsters.

And following their assembling with their fellow Young Avengers to form the titular group and a number of confrontations with both the Avengers regarding the fledgling super team’s origins, the pair eventually discover that, like Billy’s MCU counterpart, their souls were ‘rehoused’ into new bodies following Wanda’s rewriting of reality.
The Vision recalls the events of the House of M to the titular team in Young Avengers Vol. 1 #11 “Family Matters: Part Three” (2006), Marvel Comics. Words by Allan Heinberg, art by Jim Cheung, John Livesay, Jay Leisten, Dave Meikis, Matt Ryan, Jaime Mendoza, and Justin Ponsor.
Admittedly, even the most dedicated and veteran of comic book readers can fondly admit that, while the story works and is integral to the history of the 616, Billy and Tommy’s origins are a bit convoluted, though honestly not wildly more so than any other given comic book character.

However, despite both this fact and the fact that other characters with much, much more ridiculous have had their origin stories adapted far more accurately (For example, Moon Knight is a paranoid schizophrenic who regularly switches between his multiple personalities and worships an ancient Egyptian Moon God who may or may not actually exist – and he got his own TV show!), the aforementioned Schaffer refused to either earnestly engage or even attempt to tackle Wiccan’s source material.
Wiccan introduces himself to the Avengers proper in Young Avengers Vol. 1 #11 “Family Matters: Part Three” (2006), Marvel Comics. Words by Allan Heinberg, art by Jim Cheung, John Livesay, Jay Leisten, Dave Meikis, Matt Ryan, Jaime Mendoza, and Justin Ponsor.
Asked “How did the writers decide how to depict Billy’s consciousness inhabiting William’s body?” during a recent interview with Variety’s Adam B. Vary, the Agatha All Along and WandaVision showrunner recalled how her first reaction upon just learning the basics of Wiccan’s comic book origins was a baffled “What? Say it again?”.

“Truth be told, I still don’t fully understand it,” she detailed. “I’m in for an instinctive plotline, Lord knows, but there were so many steps and so many characters, and I just had no patience for it.”

Noting that the current culture at Marvel Studios considers the original comics as ‘suggested reading’ rather than ‘story guidelines’, Schaeffer ultimately added that she made the change to Billy’s origin because “You want the story to feel correct and familiar, but also still shock and surprise you.”
Wiccan and the Scarlet Witch are reunited in Avengers: The Children’s Crusade Vol. 1 #6 (2010), Marvel Comics. Words by Allan Heinberg, art by Jim Cheung, Mark Morales, John Livesay, Dave Meikis, Justin Ponsor, and Cory Petit.