Agatha Harkness is a fictional character from the Marvel Comics universe. She first appeared in 1964 and is known as a powerful witch and a mentor to Wanda Maximoff, also known as the Scarlet Witch. Agatha has a complex history, often oscillating between ally and antagonist in various storylines. In the Marvel Cinematic Universe, Agatha Harkness is portrayed by Kathryn Hahn in the series WandaVision. The character is depicted as a neighbor with a mysterious past, ultimately revealing her true identity as a witch with significant magical abilities. Her character explores themes of power, manipulation, and the consequences of magic.