Heading into WandaVision, it was pretty obvious that Agnes would ultimately be revealed as Agatha Harkness, but that made the "Agatha All Along" sequence no less satisfying.
In the final couple of episodes, we learned that her plan was to steal the Scarlet Witch's power for herself, and while the door was left open to Agatha being portrayed as Wanda's mentor, she was very much the villain in this series.
During an interview with Entertainment Tonight, WandaVision showrunner Jac Schaeffer was asked whether Agatha was part of Kevin Feige's plan or someone she chose to add to the series.
"No," she says of the latter point. "They had a lot of like, 'Maybe this character, maybe this character,' and Agatha was central in that conversation. In the early stages, she functioned as more of a mentor, and then as we got into the room and started really legitimately breaking the episodes, it became clear that having more of a proper antagonist would serve the structure really well, so she increasingly moved in that direction."
"But we didn't lose sight of the potential for her to be a mentor and a teacher and a partner and a confidant. All of that still infused all of their scenes together. And we like to say that there's a version of the story where Wanda and Agatha walk off into the sunset together, you know? You could kind of see it, and I think that led to better writing for the two of them, those gray tones in there."
It wouldn't be at all surprising for Wanda to turn to Agatha for help in Doctor Strange in the Multiverse of Madness, though we've heard nothing about the actress being part of that sequel just yet. Either way, the character definitely has a future in the Marvel Cinematic Universe, and given how popular Hahn's work was, there's no way Kevin Feige won't want to bring her back ASAP.
What do you hope the future holds in store for Agatha Harkness in the MCU?