Mortella (voiced by Linda Garry) is the villainess of the She-Ra: Princess of Power episode "Enchanted Castle". She is a beautiful but evil sorceress who rules the titular place, until she is defeated and destroyed by She-Ra (Princess Adora) with the help of Bow and the good sorceress Castaspella.
Mortella with her Magic Knights
Mortella with the old-woman Castaspella at her magic fire
Some years before Adora defected from the Evil Horde to join the Great Rebellion, Castaspella was dethroned by the evil Mortella, whose powers came from a magic fire lit inside Castle Mystacor. As long as the fire burned high, Mortella's powers were at their peak. She conjured up a small legion of Magic Knights out of the flames to do her bidding and put a spell on Castaspella that transformed her into an elderly woman, greatly diminishing her magical powers. Under Mortella's rule, Mystacor became a dark and foreboding place. Castaspella was banished to the Dark Forest, where she was allowed to gather magical powders and herbs for Mortella and bring these to Mystacor to receive a meager payment. However, Castaspella was not allowed to leave the forest, for Mortella had grown so powerful that she would always be able to find her again.
Bow confronting Mortella
Mortella uses her magic to protect herself from Castaspella
The Magic Knights captured Bow and Adora, whom Mortella wanted to use as slaves and ordered to make sure her flames did not burn low. Having met and been helped by the two Rebels earlier, Castaspella took it upon herself to free them. When She-Ra appeared and began easily defeating Mortella's Knights, Castaspella grabbed her chance to confront her old adversary to put an end to her evil reign, but was defeated again. However, before Mortella could kill Castaspella, She-Ra used the water from the lake around Mystacor to douse the magic flames. With her source of power gone, Mortella disappeared, and Castaspella regained her true form and rightful place as ruler of Mystacor.