Nobody

Nobody is a Batman-like masked vigilante who desires justice in the world.

Mirage comics
Nobody helps Casey Jones and a mutated Raphael in Tales of the Teenage Mutant Ninja Turtles #60 (July, 2009)

2003 Series
Nobody was once a New York cop, who was on the verge of exposing Ruffington as a arms dealer to the black market. But Ruffington claimed he was harassing him and the commissioner reassigned him to Archive duty. Angered at the loss of his life and his honor, Nobody 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. He wasn't disturbed by their appearance and they worked together to investigate Ruffington, as he was in league with the Shredder, modifying Triceraton weaponry for more powerful uses. Nobody fought Ruffington in his helicopter and managed to get him handcuffed, just as the police arrived.

Later with the help of the Turtles Nobody broke up the street gang "The Turks".

Nobody later joined the Justice Force.

Lost Season
Nobody was part of the final attack on the Tengu Shredder.

Fast Forward
Nobody appears in the episode "The Journal."

Back to the Sewer
Nobody has been confirmed to be in TMNT: Back to the Sewer.