Cosmo the Seedrian is the tritagonist from Sonic X.
Cosmo is a female child of a plant-like alien species whose homeworld was destroyed by the villainous Metarex.
She's an ally of Sonic the Hedgehog and his friends. It's widely accepted that her primary purpose in the series is that she has a love interest for Tails, the two characters being the same age and displaying an overt fondness for one another. In the English version, she is voiced by Amy Birnbaum who also voices Charmy Bee. In the French Version, she is voiced by Marie Lenoir who also voices Rouge the Bat since Sonic X.
Personality
Cosmo is a kind and gentle character though she often feels guilt, 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.
Trivia
Cosmo shares similar qualities with Maria Robotnik and Tikal the Echidna.
Both Maria and Tikal sacrificed themselves to save their friends/beliefs and are pacifists, but know how to fight when necessary.
According to answers.com, Cosmo turns into a seed in the Japanese version due to Chaos Regeneration... http://www.answers.com/Q/What_happened_after_Cosmo_died_on_Sonic_X
