As Disney+'s WandaVision begins to approach the final month before its highly-anticipated premiere, the newest trailer for the series reveals a major clue as to the identity of a mysterious character.One cast member has yet to have a named character: Kathryn Hahn. She's advertised as simply the "nosy neighbor" to Wanda and Vision as they travel throughout sitcoms of the decades. However, her costume in the new trailer indicates she's a major character from the comics who had a massive impact on Wanda's life.RELATED: WandaVision Unites the Show's Different Eras, Teases New Costumes, in a Stunning PosterOn Twitter, writer Nick Marino posted several screenshots from the trailer of Hahn wearing a blue, white and gold brooch. He draws comparisons from her brooch to one of Marvel character Agatha Harkness. Since her debut in 1970, the character has worn that around her neck, so it would make sense that an iconic part of her look would make its way into a possible television adaptation.

Agatha Harkness was first introduced as the governess of Franklin Richards. When the Frightful Four came to abduct the boy, she dispatched them with ease and admitted to the Fantastic Four that she is a witch. She had previously been a member and leader of a witch colony in New Salem, Colorado. She even had a son Nicholas Scratch, who became a foe of Marvel's First Family.

Agatha later serves as a mentor and guide for Wanda Maximoff in the comics. She first becomes her magical tutor in Avengers #128, helping guide the young woman through her extraordinary, yet unstable powers. Even after the New Salem community killed her by burning her at the stake, Agnes appeared in astral form to Scarlet Witch, helping her channel energy from a battle to become pregnant with Vision's children.

Her role as guardian for Scarlet Witch appeared most prominently in a fight against Mephisto in Avengers West Coast, where she had returned after her death with seemingly no explanation. Mephisto revealed that her children were fragments of his soul and reabsorbs them to prove his point. Wanda was left shocked and traumatized, and Agatha chose to wipe her memory to make her forget her children. Soon after, Agatha chose to return those memories to her protege to get her out of a complex plan from Immortus.

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Agatha Harkness

If Hahn's character is indeed Agnes Harkness, her role in WandaVision is that much more defined. From the trailers, she seems to be the only presence besides Wanda and Vision who moves through time, a show of both her magical powers and importance in Wanda's life. Moving in next door could allow Agnes to always have a close eye on Wanda, as well as being able to lend a listening ear and advice. Set photos previously showed Hahn and Elizabeth Olsen dressed in 17th-century attire doing magic, so she may eventually reveal her true self to Wanda during the show's first season.

While this proves an exciting prospect, it also may foreshadow an unhappy ending for Agnes. In the comics, though Wanda was able to help defeat Immortus after her memories were returned, she killed her teacher in retribution. Considering the vulnerable state Wanda is in post-Endgame, if Agnes tips her off to keeping a hold on her, that may push Scarlet Witch over the edge.

Written by Jac Schaeffer and directed by Matt Shakman, WandaVision stars Elizabeth Olsen as Scarlet Witch, Paul Bettany as Vision, Randall Park as Agent Jimmy Woo, Kat Dennings as Darcy Lewis, Teyonah Parris as Monica Rambeau and Kathryn Hahn as Agnes. The series premieres Jan. 15, 2021 on Disney+.

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