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Fiona Fox is a red female Mobian fox from the Sonic the Hedgehog comic book series by Archie Comics. She once lived a life of crime, but later in life, she became a Freedom Fighter who fought alongside the heroes, Sonic the Hedgehog, Miles "Tails" Prower, Sally, Bunnie Rabbot, Rotor Walrus, Amy Rose, and others. It turned out she was into the bad boys, and went out with Sonic's evil counterpart, Scourge the Hedgehog. Now, she is a villain who leads the Destructix, a gang of criminals. She has gained many fans, but has also garnered her fair share of haters in the Sonic community.
Fiona Fox will appear in Sonic Final Battle Genesis, where she is a teammate of Team Blossom (formerly known as Team Rose) along with Amy Rose and Bunnie Rabbot. She replaces former Team Blossom member, Cream the Rabbit (who had quit the team along with Big the Cat due to growing tired of Amy's rude and bossy attitude). When Amy's place is under attack by Metal Sonic, Tails Doll, Metal Knuckles and Amedroid Rosebot, Fiona comes in with Bunnie Rabbot to chase them off, because they know they are after something important to the game's plot. She and Bunnie have pity on Amy and let her go with them.
Fiona makes an appearance in Sonic Heroes 2 as the acerbic inhabitant of Mystic Ruins. She is also revealed to be the source of mysterious instructions in Team Chaotix' storyline and makes an appearance in Team Archaic's storyline.