Fiona Fox is a supporting antagonist in the Archie Comics of the popular Sonic the Hedgehog franchise. Originally, she was one of the many victims of Dr. Ivo Robotnik's rise to power and was imprisoned as a child as a result of being abandoned by Sonic the Hedgehog and Mighty the Armadillo.
Understandably, Fiona developed a grudge against the two for what happened and over time her grudge worsened the darker aspects of her personality until she eventually fell from grace entirely and became an outright villan.