Ben Tennyson was abducted by aliens when he was ten years old after accidentally acquiring the Omnitrix, but he was later rescued by Tetrax. Tetrax also brought Rook Blonko to his side. Both Ben and Rook were orphans, and Tetrax trained them to become "space vigilantes." When Ben reached his teenage years, he received the Ultimatrix. At eighteen, Ben and Rook decided to return to Earth, where they were unexpectedly taken under the protection of the Justice League.
