She was voiced by Kathleen Barr.
Role in the film
Lydia was a muse of the Diamond Castle, but was jealous of the other muses, wanting to be the only one. She vowed to eventually have the Diamond Castle all to herself.
Lydia turned her flute into a weapon and hid in a cave filled with dark magic. When her minion Slyder, detected the presence of Melody, she tracked her down, trying to get the mirror so she can find where the Diamond Castle was hidden.
Lydia attempted to trap the girls in a mansion by hypnotizing two residents that lived there, but only succeeded in catching Alexa. Slyder kidnapped Liana and took her back to the lair.
Lydia used her flute on Alexa and made her almost fall off a cliff into boiling hot liquid, but Melody saved her by confessing where the Diamond Castle was. Liana and Alexa followed Lydia and defeated her, and found the Castle. They saved the muses and used their music to defeat Lydia forever.
Lydia is an extremely cruel, cunning, deceitful, manipulative, villainous, and selfish woman who will stop at nothing to achieve her goals. She is also extremely prideful, cocky, arrogant, and presumptuous, believing that she was perfectly capable of being the one and only Muse, and that her magic made her invincible.
Lydia has reddish-brown hair, fair skin, and green eyes. She wears a maroon and black gown, and around her neck is a necklace that is shaped like a snake biting its tail. Her hair is piled atop her head. She is always seen with her flute, the color of which was silver and white before her fall from grace turned it into red and black.
However, in the junior book of the movie, it was shown that Lydia originally wore a white and gold Grecian gown similar to those of Dori's and Phaedra's.