Considering that Agatha All Along is a spinoff from WandaVision, Disney Plus’ first proper MCU television series, there are naturally many links to its predecessor. Several inhabitants of Westview return for this show, both as players in Agatha’s spellbound detective drama dreamscape, as well as ordinary citizens in the real world. Senor Scratchy is also still around – he was the pet bunny that Agatha lent to Wanda for her magic show in WandaVision. Early on, the pendant that Agatha finds in the woods is the same one she wears throughout WandaVision.
In the pilot, Agatha searches for the book from a dead body’s library slip, before she learns it is the deceased Scarlet Witch. At the library, within the “true crime” hex, first she is told that the book was stolen, and then she sees that all the copies were burned. This is a reference to the Darkhold, which was taken by Wanda before all the Darkholds are destroyed in Doctor Strange in the Multiverse of Madness.
The inciting event of Agatha’s newfound magical freedom is the death of the Scarlet Witch. As seen in the Doctor Strange sequel, the Darkhold turns Wanda into a villain, who terrorizes Miss America Chavez and slaughters heroes across the multiverse. Wanda is ultimately crushed under Mount Wundagore after sacrificing herself, which is alluded to in Agatha All Along.
When Agatha is assembling her coven in the second chapter, the only member that is missing is a Green Witch. The teen asks who was on the list of recruits to fill this role, but instead of a name, there was a heart. Since the heart was black, it really represented Rio Vidal, Agatha’s rival (though we later learn that it was actually referencing Billy Maximoff), yet Agatha played it off as meaning Mrs. Hart from Wanda’s fictional hex. This correlates directly with the WandaVision pilot, where a heart drawn on the calendar signifies the newlyweds' dinner plans with Mr. and Mrs. Hart.
In the following episode, Mrs. Hart is the first to be poisoned and hallucinates. She shrieks “Wanda, please let him breathe!”. This is also a callback to that awkward dinner in WandaVision; Mr. Hart chokes on his food and is almost past the point of recovery until Vision uses his phasing abilities to remove the food. During Agatha’s hallucination, the Darkhold is in a cradle in place of a baby. Again, the Darkhold was significant in previous mystical narratives, WandaVision and Multiverse of Madness.
Agatha All Along’s fourth episode does not have many direct connections to the larger franchise, aside from a few references to vampires and werewolves. While these monstrous species have yet to make much of an impact in the MCU movies (unless you count the daywalking Blade’s formidable comeback in Deadpool and Wolverine), the vampire Saracen attended Abomination’s therapeutic retreat in the She-Hulk show and Jack Russell was front and center in the Disney Plus special presentation Werewolf by Night.
Around the midway point of the limited series, the Teen’s identity is uncovered. He is Wanda’s magical son, who has grown into a teenager, played by Heartstopper star Joe Locke. He wears a crown that is similarly designed as the Scarlet Witch's. Her color scheme is Scarlet red, while Billy’s is Wiccan blue.
The show’s sixth episode is all about Wiccan, following every step that was taken leading up to Wanda’s son inhabiting the dead body of a young man named William Kaplan, who died in a car crash. This occurs as Wanda’s hex over Westview dissipates, lining up with the WandaVision finale, so Billy Maximoff was disappearing around the same time and managed to transfer into a new body. Marvel fans may recall Professor-X accomplishing this exact same feat in X-Men: The Last Stand, but that non-MCU parallel may be unintentional.
Years later, Billy explains the transference to his boyfriend Eddie. It turns out that the Westview anomaly, instigated by Scarlet Witch, was “officially” declared an Avengers training exercise mishap. This is an amusing allusion to the MCU’s first movie, Iron Man, when Rhodey covers up Iron Man’s mid-air scuffle with the Air Force by reporting to the press that the whole ordeal was just a training exercise.
Also in part six, Evan Peters makes a comically pleasing return as Ralph. He was mind-controlled by Agatha in WandaVision to portray Wanda’s deceased brother Quicksilver - of course Peters played Quicksilver in the X-Men movies (not in the MCU though). Ralph reveals to Billy and Eddie that Agatha forced him to kill the family dog, Sparky.
In the miniseries’ seventh inning stretch, Rio is finally revealed as the personification of Death. Now viewers know why she was laughing when the Ouija board, in an earlier episode, spells out “Death”. Death was famously teased during the mid-credits’ scene in The Avengers, when the Other tells Thanos, to challenge the Avengers is to court Death.
At that time, Marvel readers could have assumed that Death was a physical character since Thanos courts her in the comic books. Ultimately, Thanos’ actual death resulted from confronting Earth’s mightiest heroes. Agatha All Along marks the formal introduction of Lady Death and her comic book connection to Thanos is not lost on this show’s creators; she thinks that Wiccan reincarnating into another body disrupts a sacred balance. That type of universal balance was a fixation for Thanos.
As the series heads towards its big finish, it becomes more clear that this is just as much Billy/Wiccan’s story as it is Agatha’s. Billy uses his immense power to locate an appropriate vessel for his brother’s essence to permeate. This would allow him to live on in a different body, the same way Wiccan has. During the process, Wiccan hears the echoes of his loving parents as they were preparing to never see their kids again in the WandaVision finale.
Agatha All Along ends with a look toward Wiccan’s future. He searches for his brother Tommy/Speed, which will almost certainly connect with an upcoming MCU project. Will Joe Locke reprise his Wiccan role in the Vision Quest Disney Plus show or in a potential Young Avengers feature film?