Fiona is a character from the *Sonic the Hedgehog* comic series published by Archie Comics. She was a key player in the "Sonic Underground" storyline and later the main character in the "Sonic the Hedgehog" comic series after the "Sonic Underground" story concluded.
While Sonic X features many characters from the Sonic the Hedgehog video games, it does not include Fiona. She remains a character exclusive to the Archie Comics universe.