Zelda is the main antagonist of The Swan Princess: The Mystery of the Enchanted Treasure. She is a cunning evil sorceress who helped Rothbart regain his powers. After Rothbart betrayed her, however, Zelda plots to gain the Forbidden Arts for herself.
It is revealed in a flashback that Zelda worked alongside Rothbart to recover the Forbidden Arts after he was banished by King William and lost his powers. Zelda wrote down the notes for the Forbidden Arts and locked them in a small chest, hidden in a room in Rothbart's castle.
It is implied that they have been lovers and that Zelda intended to rule by Rothbart's side as his queen, once he took over William's kingdom. However, when Rothbart regained his powers, he betrayed Zelda, revealing he intended to marry Princess Odette instead. When Zelda protested, arguing that without her, Rothbart would be nothing, he threatened her life, forcing her to leave. However, Zelda vowed that one day, she would return for the notes and gain knowledge of the Forbidden Arts herself.
A few years after Rothbart's death, Zelda captures a yacky bird named Whizzer and forces him to help her sneak into the castle to find the notes; in exchange, she will give him his freedom. When she learns the notes still exist, Zelda pretends to be a servant girl from the 'far North' and seduces Lord Rogers, who falls madly in love with her and invites her back to the castle.
Zelda retrieves the notes and gains the power to create and change, but discovers that Prince Derek has torn the end of the page for the power to destroy. Zelda uses a green 'seeker' to kidnap Derek's wife Odette, along with Jean-Bob as a stowaway. She ties her up, but Odette manages to get free, though not for long - Zelda sees her fleeing and turns her into a swan, then traps her in a deadly green fireball.
Zelda then waits for Derek to arrive and give her the notes that he had hid in his library; she disguises herself as Odette to trick Derek and takes the note. Odette manages to escape a second time and Zelda sends a red destroyer seeker after her, intending to kill her. Odette is unable to fly away fast enough and is killed. Zelda tries to kill Derek too, but is betrayed by Whizzer, who helps to distract her by impersonating Rothbart's voice. Derek makes a grab for Zelda's wand and during the struggle, Zelda falls backwards into the green fireball where she had imprisoned Odette and Jean-Bob, and she is destroyed. Odette is also restored to life after Zelda's death, when Derek burns the notes.
Zelda has a long, blonde hair, a long nose, and pale skin. She uses a purple eyeliner, thick red lipstick, and black nail polish. She wears a black dress with a red cloth wrapped around her wrist.
Zelda uses a magic wand to create seekers which are green fireballs or 'seekers' that can find and capture their intended target no matter where they go and bring them to her.
Once Zelda got hold of Rothbart's notes, she gained the powers to create and change, but she could not obtain the power to destroy; even though she had the note, the last word had been torn off, so she kidnapped Odette for ransom. When she did obtain the power to destroy, she could create a red seeker that could destroy their target upon contact.