Cosmo is kind and gentle, though she often feels guilty because she was unable to save anyone from her home planet ever since the destruction of the Metarex. She also seems to suffer from a low self-esteem issue, often calling herself "unworthy" or blaming herself for the hardships that she and her friends had to endure. Cosmo also dislikes violence, but acknowledges that fighting is sometimes a necessity, although she herself is unable to fight. Cosmo can be somewhat clumsy, but she is also quite resourceful; she also has a penchant of getting into trouble. While she would never fully admit it, she’s madly in love with Tails. After appearing in the canon Universe, her personality is untouched, though she's become violent on the rare times she's angered.

She is voiced by Amy Birnbaum, an example of her acting can be found here: https://youtu.be/U7hBXrEq7us?t=430