Rumored to have been killed when the atomic bomb was dropped on Nagasaki, Asano Nitobe was an urban legend among martial arts enthusiasts in the 1970s, as the Last Living Grand Master of Ninjutsu. Nitobe had left Nagsaki just days before the bomb dropped to serve as a body guard for Dr. Oka a geneticist who went on to serve the Council. After Dr. Oka's death, Nitobe continued to serve the Council and trained Paul Kirk (The Manhunter). When Kirk defected, Nitobe engaged him in combat. Nitobe, a victim of the council's brainwashing, was unable to believe anything Kirk said about the council and was about to slay Manhunter when Christine St. Claire arrived and played a tape of Council member Dr. Mykros explaining how the Council had ordered Dr. Oka killed. This allowed Nitobe to overcome his brainwashing and ally with Manhunter in a final attack designed to bring down the Council.
The Council was wounded but never destroyed and continued it's machinations long after Paul Kirk death, using his clones to carry out their operations. Over several decades, Nitobe and Christine St. Claire dedicated themselves to hunting down and destroying all of the clones. When Kirk DePaul joined the Power Company, Nitobe and Christine St. Claire confronted him. He was able to convince them that he was not a tool of the council, despite being a clone of Paul Kirk, but the two felt uneasy letting him live and continued observe him, ready to take him out the second he showed any sign of being under the Council's control.
Nitobe has also trained others such as Freeway (a metahuman criminal) and Nemesis (Sosesh Mykos), daughter of the head of The Council.
Nitobe is a Grand Master of Ninjutsu, the Japanese spy art which involves mastery of almost all other forms of martial arts. As such, he is a master of various forms of unarmed and armed combat. Though he prefers medieval Japanese weaponry, he is adept in the use of modern weapons as well.