Nobody was a superhero that later joined the Justice Force. His primary vocation was that of a police officer, but at night, he went after an arms dealer named Ruffington outside of the boundaries of the laws he'd have to follow as an officer.
The reason why Nobody was after Ruffington was because he got Nobody fired from his job as a Police detective. Nobody was once a New York City police officer, who was on the verge of exposing Ruffington as an arms dealer to the black market. Ruffington issued a complaint that he was harassing him. This results in the Police Commissioner reassigning him to archive duty. Angered at the loss of his life, reputation, and honor, the police officer became Nobody and strove to expose Ruffington.
In the aftermath of the Triceraton invasion, Nobody was on to Ruffington. While chasing one of Ruffington's trucks, he saved Leonardo and Michelangelo from being run over. Subsequently, they worked together to investigate Ruffington, who was in league with the "Purple Dragons" and Hun (and thus indirectly the Shredder), by modifying Triceraton cannons and dealing them to the Foot Clan. Nobody fought Ruffington and managed to get him handcuffed, just as the police arrived. Once he succeeded, Ruffington asked who we was and he said "somebody".
The Lost Episodes
Once they won, Nobody wasn't seen until the TMNT: Fast Forward episode "The Journal." April and Casey's journal's entry on Michelangelo mentioned that he and the other Justice Force members were (supposedly) accidentally turned into toddlers by none other than the Turtle Titan, when he deflected Big Bad Binky Boy's ray. It turned out that the Journal was a fake and has been made to fool the Turtles into not seeking out the real journal.
Back to the Sewer
In TMNT: Back to the Sewer, Nobody appears in the episodes Super Power Struggle and Wedding Bells and Bytes. Nobody and the Justice Force were invited guests at the wedding of April and Casey. While they arrived late to the ceremony, they came just in time to save the other guests from an attack by the Cyber Shredder and the Foot Clan.
- Nobody is a homage to the DC Comics superhero Batman. Like Batman, he possesses no innate superhuman powers, his principal antagonists are the corruption and organized crime, he broods and wears a predominantly dark outfit.
- His name is a reference to the Odyssey.