He-Man and the Masters of the Universe (1983)

S02E12 Origin of the Sorceress

The Sorceress discovers that her longtime foe, Morgoth, is trying to make a comeback in Eternia. Determined to confront this threat, she shares with He-Man the story of her initial confrontation with Morgoth, which ultimately led her to embrace her role as the Sorceress of Grayskull.