The Ninja Master (real name: Nakahara), also called the "Masked Ninja", is an evil ninja who is the leader of the Zeed crime syndicate and the main antagonist from Shinobi and it's two sequels, The Revenge of Shinobi and Shinobi III: Return of the Ninja Master. He attacks Joe Mushashi with his long hair and uses it as a boomerang also. In Shinobi III: Return of the Ninja Master, he has new attacks, such as shooting needles out of his long hair, and throwing bansho fans.
Nakahara was once the mentor of Joe Musashi, but he had another persona; the Masked Ninja in charge of the Zeed Crime Syndicate. He had his soldiers kidnapped the children of the Oboro Ninja School, prompting Joe to save them. His plan was to send the world back into war, so that the Ninja could have a second chance at glory, but he was defeated by Joe.
The Revenge of Shinobi
The Masked Ninja returned as the leader of the criminal organization called Neo Zeed. He appeared in the last level where Joe confronts him in a final showdown. The Ninja Master trapped Joe's bride, Naoko in a cell trap where it can kill her. Joe defeated the Ninja Master and rescues Naoko and reunites with her.
Shinobi III: Return of the Ninja Master
Neo Zeed resurfaced under the command of the "Shadow Master"; Nakahara revived in a cyborg form. The Shadow Master gets revenge on Joe for defeating him in the past. Joe once again defeats the Nakahara killing him for good.
- Nakahara's name is a reference to the Musashi-Nakahara Station. His name is meant to be a hint of his true identity as "Nakahara Musashi", Joe Musashi's father.