The finale of Loki brought the MCU into the Multiverse. Loki proved to be both entertaining and confusing, but it seemed to perfectly set up Doctor Strange in the Multiverse of Madness. However, Loki has presented an a potential explanation to an earlier Marvel series. WandaVision's post-credits scene left a few scratching their heads, but Loki may have just offered an answer.
In the post-credits scene of WandaVision, Wanda is seen in an isolated cabin, leaving Westview and its repercussions behind. While she enjoys a cup of tea, her astral projection (wearing her new Scarlet Witch costume) reads from what appears to be the Darkhold. The final moments of the scene feature two faint voices calling out to Wanda. Those voices appear to be her children Billy and Tommy begging for her help.
Those who watched WandaVision know that after Wanda and Agatha's showdown, Wanda relinquished the hold she had on Westview and its citizens. Wanda began to dismantle the Hex and by doing so, she gave up Vision and the small life they'd built together in Westview, including their children Billy and Tommy. As the Hex finished undoing itself, Wanda and Vision's heartbreaking goodbye made it clear that what had once existed in Wanda's version of Westview no longer remained.
If all of Wanda's version of Westview vanished, it prompts an interesting question: how did Wanda manage to hear her children calling out to her? Luckily, Loki has offered an explanation. In the Loki finale, Sylvie disobeys Loki's wishes and kills He Who Remains. When Sylvie does this, she reopens the Multiverse. Loki's answer to the WandaVision post-credits scene is simple. When the Multiverse began to take form, Wanda heard Billy and Tommy's voices.
This would mean that the branches of the Multiverse and WandaVision's post-credits scene overlap. If Tommy, Billy, and Vision disappeared from Westview, where is it they disappeared to? As proved by the TVA's pruning technique, disintegrating before someone's very eyes doesn't always mean that they're dead. It's possible that when the Hex disappeared, taking Wanda's fabricated Westview with it, it became another variation within the Multiverse. No longer present on her own timeline, Wanda would have been unable to hear Billy and Tommy until Sylvie opened the gateways to all the others, where they may be trapped.
If true, it raises a number of other questions. One of those is where are Billy and Tommy? The simple answer is that they're stranded in another universe. Loki's final moments support this. Aware of what Sylvie has done, Loki runs to Mobius and Hunter B-15 only to find that neither of them knows who he is. This means that when Sylvie pushed Loki away, he was likely pushed into another universe.
Now that the Multiverse has been opened, will there be other versions of Tommy, Billy, or even Vision? If so, what will they look like? In Loki, there were dozens of variants that took a number of forms (including an alligator). He Who Remains also mentioned a number of his own variants that began a Multiverse war that he ended. In fact, Loki's final shot showed one of those variants: a statue of Kang the Conqueror. If Wanda has indeed heard her children across the Multiverse, it is possible that the voices she heard aren't from the same Billy and Tommy that were in Westview.
In Westview, Billy and Tommy had just come into their powers and hadn't quite mastered them yet. Tommy was equipped with super speed much like his uncle Pietro Maximoff. His twin brother, Billy, appears to take after their mother. Throughout WandaVision, Billy exhibited a number of powers. Among them are telekinesis, telepathy, and precognition.
Billy uses his telekinetic powers to stop Hayward's bullet during WandaVision's finale. While Wanda has been known to stop a number of things with her mind, the most striking resemblance to his mother is his telepathy. In Age of Ultron, Wanda seemed to feel her brother's life drain from his body. In response, she unleashed a form of chaos magic resembling what created Westview. Once Vision attempts to cross the Hex, Billy feels his father's distress in a similar manner.
While Billy and Tommy first acquired their powers in WandaVision, if there are variant versions of them across the Multiverse, will they have more control over their powers? As fast as Billy and Tommy aged in WandaVision, it's possible. Billy and Tommy may have come into their powers at a different time, appear much older, and because of that age difference, they may have had more time to harness and control their abilities.
Of course, if Billy and Tommy had the potential to reappear as themselves or as variants, there is a chance Wanda may see a few other familiar faces. Wanda could come into contact with a variant version of herself, Pietro, or Vision. During their final scene, Wanda and Vision did promise they would say hello again. While it may not be in the way either of them anticipated, no matter how Wanda comes into contact with Vision, it's going to be an emotional reunion.
Confirmed to appear in Doctor Strange in the Multiverse of Madness in addition to her post-credits scene, it is clear Wanda will attempt to find Billy and Tommy. After all, they are the last living piece she has of Vision and their life in Westview. But, if they are not the Tommy and Billy she knows, it may lead to more disappointment for Wanda. If that happens, there's no telling what she may do next.
All episodes of both Loki and WandaVision are now streaming on Disney+.