Hayate Musashi (in Japanese: 疾風・ムサシ) is the estranged son of the legendary Joe Musashi and the protagonist of the Japanese version of the Shadow Dancer: The Secret of Shinobi. In order to give his family the opportunity to live a better life, Joe Musashi sent Hayate and his mother away on a small raft as he fought a group of shinobi that attacked them after he went rogue. Adopted by the Japanese-American dojo instructor, Dick C. Kato, Hayate grew into a young man with a good heart and resolute spirit. When his adoptive father was killed by Union Lizard, a syndicate that sought to take the place of the defunct Neo Zeed, Hayate went with his faithful dog Yamato to seek revenge.
Hayate is a well built man who wears white ninja armor, with a sleeveless red chain mail shirt, and black pants. He dons a shinobi kabuto over his head and a cloth mask over his lower face to hide his identity. He carries a sword, which may possibly be the legendary Oborozuki of the Oboro clan.
In the winter of 1977, in Japan's Iga province, Joe Musashi and his wife Naoko (ナオコ) took their young son Hayate and fled the Oboro village. Joe Musashi was being chased by unknown assailants, and it was because of this that he decided to become a rogue ninja. Joe didn't want his wife and child to deal with the torments and dangers of life as a shinobi, so he lead his family to a small vessel upon which they could escape. However, when Joe and his family reached the small raft, they discovered that it could only accommodate two people and, with a heavy heart, Joe sent his wife and his son, and their dog Yamato (大和), to safety as he engaged their pursuers in combat. This would be the last time Hayate would see his father's face.
In the spring of 1978 and at a mist covered Brooklyn harbor, Dick C. Kato found Naoko and Hayate in the middle of his jogging routine. Naoko was already gone, but Hayate and Yamato were safe. As Kato inspected the child, he found a shuriken in Hayate's little hands. Surprised to have found a ninja artifact, he suspected that the child may in fact be a young ninja. Kato took Hayate and Yamato and raised the one year old boy as his own son.
By the summer of 1997, Hayate, who had trained with Kato since his childhood, grew to be an amazingly talented martial artist. Because ninja were naturally familiar with not only the mystic ways of ninjutsu but all martial arts as well, Kato marveled at Hayate's prowess and really did wonder if he was a true shinobi's child.
While they lived in peace, a mysterious terrorist group butchered countless innocents in the city. Some of its members were ninja, and the citizens' fear and terror intensified. One day, when Hayate returned from practice, he encountered an injured Kato, who was attacked by the mysterious group. Kato, the man who mercifully took him in as his son, had died. With a fierce rage, sorrow, and resentment within him, Hayate grasped a ninjatō, which was a memento from his real father. It was then that Hayate's dormant Oboro ninja blood had awakened. Hayate marched on to avenge his adoptive father, with Yamato at his side.
Hayate cut through a swathe of terrorists, and fought until he met the monstrous chief of Union Lizard, the mutant who took Kato's life. With rage burning, Hayate focused all his skills on destroying the monstrous villain until at last the battle was over.
As he paused to gaze back at the Statue of Liberty with his dear dog Yamato, Hayate departed to face his destiny as a ninja.
Hayate, like his father, is a man of duty and honor. Although he never knew his real father, he was more than happy to take up his blade. He loved his adoptive father and mentor with all his heart, and was devastated when Union Lizard began its rampage. Together with his canine companion, Hayate faces his destiny as a lone ninja.