- Cassie is highly intelligent, loyal, and an extremely logical thinker who plans every step before she takes it. Cassie usually never breaks the rules, but she has one exception: Bitty, her pet glowfur – which she is not allowed to have at school!
- —Official description
Cassie is a first-year student at Starling Academy with one of the other twelve Star Darlings and one of the supporting characters and protagonists in Disney's Star Darlings.
Describing Cassie's personality, she is extremely imaginative, super smart, loyal, highly intelligent, extremely logical, shy, friendly, artistic, and very intuitive. On the other hand of her personality, she can be distrustful, jealous, moody, bragging, hypersensitive and brooding.
- Cassie is named after Cancer, the fourth of the twelve astrological signs of the zodiac, which means the crab.