Casta Fierce is the daughter of Circe and the lead singer of Casta and the Spells in Monster High.
Casta has long black hair with purple and orange highlights on her fringe and green skin. She also has a beauty mark. Her outfit consists of a sparkly dress that is purple and orange that cascades into a flowing orange and black net with a black belt. She has on spiked purple boots, a fishnet arm warmer, and holds a purple broom with orange ribbons and a purple microphone.
Casta is a close friend of Catty Noir, a fellow but younger singer who has put her career on pause to return to a regular life. Supposedly, Casta also is close with her fellow band members.