Agatha Harkness may have made her MCU debut in WandaVision - complete with her own theme song - but fans of Marvel Comics have spent more than 50 years reading about the witch's two-faced ways. Similar to Scarlet Witch, Agatha Harkness's powers have changed and evolved over the years, but one thing's for sure: She's one of the most experienced magic users in the comics. Also, when it comes to Agatha Harkness, Mephisto and other mystical villains are rarely far behind.
In her first appearance (1970’s Fantastic Four #94), Harkness started out as a nanny for the FF with a dark, magical secret. Since then, she’s evolved into a supporting character for many mystical Marvel heroes, and the Scarlet Witch in particular. Whether it be the sudden appearance and disappearance of Wanda Maximoff’s children, her eventual mastery of chaos magic, or her tragic descent into madness, Agatha has been there for Scarlet Witch's entire journey. Dead or alive (and she’s been both with great regularity), Harkness has built a reputation as a generally benevolent individual with little more than a touch of moral ambiguity - a sharp contrast to the strong villainous undertones of Kathryn Hahn’s portrayal in the MCU.