When Disney released the trailer to the upcoming Marvel series Agatha All Along, it opened with star Kathryn Hahn humming and driving a car. We see her pull up to a crime scene and it turns out, she's a detective.

But not for long because while she's in the morgue finding out that the body is Wanda Maximoff's, Aubrey Plaza's Rio Vidal is there to remind Agatha of who she really is. As Rio tells her to “claw your way out!” she transforms into different women before becoming the nosy neighbor in WandaVision.

So who is Agatha Harkness?

Disney+ drops exciting first look at upcoming Agatha: Darkhold Diaries

She was created by writer Stan Lee and artist Jack Kirby and first appeared in issue 94 of Fantastic Four in October 1969. She was one of the original witches who survived the Salem witch trials. In Fantastic Four, she was governess to Franklin Richards, son of Reed Richards (Mr. Fantastic) and Invisible Woman (Susan Storm), and the Fantastic Four's ally.

More recently, she was introduced to the Marvel Cinematic Universe in the Disney limited series WandaVision as the couple's nosy neighbor Agnes. According to Hahn, Agatha's relationship with Wanda is akin to that of Antonio Salieri and Wolfgang Mozart.

“We talked a lot about Amadeus and Salieri, in terms of their relationship — Agatha wishes that she could make the kind of music that the Scarlet Witch just had naturally. For someone that has spent centuries studying this, to meet a young person to whom it comes completely naturally, it's maddening and you want to know why,” the actress told The New York Times.

Agatha, as written in the comics, is almost immortal. She has been around since the ancient times being old enough to remember half a millennia before Atlantis was destroyed. In the late 17th century, she settled in the English colony of Salem, Massachusetts. There, she formed her own coven to hopefully freely practice magic. However, her group was persecuted during the trials.

She took the rest of her coven who survived and resettled in somewhere in Colorado in the hidden mystical city of New Salem, only accessible to those who have magical powers. Agatha married and had a son, Nicholas Scratch. However, she eventually left and went into the city.

The Daughters of Liberty

At the end of the 18th century, Agatha joined the Daughters of Liberty. They are an all-female group whose mission is to protect the freedom of everyone at all costs. She used her knowledge gained through the centuries to train the women in the mystical arts.

Agatha met Wanda Maximoff after her stint as a governess. When she sensed Wanda's desire to learn how to control her powers and offered to tutor her. Agatha trained her until her marriage to Vision.

In New Salem, her son Nicholas had seven powerful children who had begun calling themselves Salem's Seven. Nicholas took control of the town with their help and told the residents that Agatha had betrayed them when she became an ally to the Fantastic Four. She was brought back to the town with Franklin and put on trial. The Fantastic Four came to her rescue and both she and Franklin were freed. Nicholas was then banished to another dimension.

However, Salem's Seven ended up taking over New Salem anyway. Once again Agatha was captured, but this time her grandchildren burned her at the stake. Wanda, as the Scarlet Witch fought Salem's Seven. In the battle, New Salem's energies were drawn into Vertigo, a member of the Seven. She lost control of the energies which decimated the entire town. However, Wanda was able to capture some of the energy and used it to become pregnant with Vision's children.

Agatha resurfaced without any explanation. She ended up working with Wanda again, who had become an amnesiac. The two have a strange teacher-mentor relationship that sometimes ends up with the teacher dying in the hands of her student.

In WandaVision

In WandaVision, Agatha sensed a confusing magical energy from Westview, New Jersey. When she arrives, she learns that the town was in a warped reality under Wanda's control. She wanted to know how Wanda was doing it, as it was greater than any magic she had encountered before. To do that, she needed to use the Darkhold (Book of the Damned) to amplify her powers and enter the anomaly as Agnes, the nosy neighbor.

In the course of the series, she insinuates herself into Wanda and Vision's life in the hopes of learning how to harness magic the way Wanda can. In the end when Wanda realizes that the life that she thought she lived with Vision wasn't real, she and Agatha fight. Since Agatha can absorb Wanda's chaos magic, she thought that the Scarlet Witch had finally agreed to give her powers to her.

However, it was all a distraction. Wanda was able to reverse what she had been doing and ultimately rendered Agatha powerless. She told her that as punishment, Agatha would be imprisoned in Westview as the ordinary nosy neighbor Agnes.

While Agatha's priority has always been to accumulate power, she has her own sense of justice. She called out Wanda's actions, telling her that heroes don't do what she did: essentially holding the people living in Westview hostage so she can live out the life she wanted with Vision. However, Agatha's main objective is still to become the most powerful sorceress in existence. She willingly uses dark magic to achieve her goals.

Agatha All Along

In Agatha All Along, she's still trapped in Westview, powerless. Her plan is to regain her powers with the help of her coven. In the show, that coven consists of the warrior witch Rio Vidal (Plaza); the 450-year-old Sicilian witch Lilia Calderu (Patti LuPone); Alice Wu-Gulliver or The Wu (Ali Ahn), who inherited her mother's powers who was the magical guardian of Hong Kong, August Wu of the Coral Shore; Jennifer Kale (Sasheer Zamata), a witch and was an apprentice of Dakimh the Enchanter; Sharon Davis aka Mrs. Hart (Debra Jo Rupp), a human and was Wanda and Vision's neighbor; and as-yet-unnamed teenaged boy (Joe Locke).

I suspect Sharon joins the coven because of how much she resented Wanda after she lifted the Hex on Westview. And as for the teen, the main speculation is that he could be Billy Kaplan aka Wiccan. It would be interesting if Locke's character does end up being Billy because he also happens to be one of Wanda and Vision's twins — at least the reincarnated version.

From the trailer, it seems like the Teen will be Agatha's familiar or her attendant in exchange for something. In Billy's case, this could have something to do with the Witches' Road, which Agatha wants to go on to restore her powers. In the comics, the Witches' Road provides magical trials and if a witch survives them, they are rewarded with what they're missing.

This would be a great backdrop for Agatha and the ragtag coven she has assembled.

We'll see if I'm right when Agatha All Along premieres on Sept. 18 with two episodes on Disney+.