Rojo is an antagonist in the Ben 10 series. She started as a leader of a group of female bikers but after inspecting one of Vilgax's drones she becomes a super droid.
Rojo robbed an armorer with her group of bikers but they were defeated by Ben Tennyson as Four-Arms who later defeated two drones that belong to Vilgax. After the battle, Rojo picks up the remains of one of Vilgax's drones which then merges with the biker. Rojo becomes a cyborg and gains superhuman strength, speed, flight and metal claws. However, Vilgax can contact the biker through the drones' former parts and coerces her into obtaining the Omnitrix for him.
Ben transforms into Upgrade and defeats Rojo by shorting her out and Gwen knocks her unconscious. She was arrested by the police after the police.
Rojo was later recruited into Negative 10 and given a new suit by the Forever Knights. She had a rivalry with Charmcaster while in the group. She and other members of the Negative 10 end up trapped in a force field.
In Ultimate Alien, she reorganizes her biker gang to rob a train only to be defeated by Rath and his allies.
- Rojo is Spanish for red.