Rojo

Joey (voiced by Jennifer Hale) is the leader of a heavily armed female biker gang. When she tries to rob an armored truck, she is thwarted by Ben as Fourarms and two of Vilgax's drones coming after Ben. The remnants of one of Vilgax's defeated drones fuses with Joey as she investigates it, and she becomes Rojo (Spanish for red), a powerful cyborg. The upgrade gives her the ability to fly, super-strength, metallic claws, and a pair of blasters attached to each shoulder. Vilgax is able to communicate with her through the parts and force her to track down the Omnitrix for him. Joey is turned back to normal when Upgrade shorts out the spare parts, after which Gwen knocks her unconscious for attempting a sneak attack on Upgrade. Joey is greedy, wild and amoral, and not hesitant to attack innocent bystanders just because they annoy her. Neither her real name or her cyborg name is mentioned in the show, except for in "Ben 10 vs. The Negative 10," where her name is pronounced with an English "j," but are listed as such in the credits. Joey first appears in the episode "The Alliance". She returns in "Ben 10 vs. The Negative 10" as part of the Negative 10, with alien tech and armor presumably supplied by the Forever Knights. In that episode she is also shown to have a rivalry with Charmcaster for being the "baddest girl" in the group.