From Ninja Gaiden Wiki
Ken Hayabusa, named Jôe Hayabusa
(ジョウ・ハヤブサ, Jôe Hayabusa?) in the Japanese version, is Ryu's father. He appears only in
the first NES game,
Ninja Gaiden (NES). At the beginning of the story, he engages Bloody Malth in a duel and is defeated. He has left a letter entrusting the family heirloom to his son, Ryu, and telling him to go to America to find Doctor Walter Smith if he fails to return home. Presumed dead, he is later revealed to be alive, under the Jaquio's control as "the masked devil". Ken manages to break free of the spell thanks to Ryu destroying the device controlling his mind. However he sacrifices himself to protect his son, by taking one of the Jaquio's energy bolts aimed at the latter.
In Ninja Gaiden/Sigma, Joe Hayabusa is mentioned by Murai in the beginning as being away in training in the sacred wilderness. Ryu is left in charge of protecting the Dragon Blade, the Dark Dragon Blade, and the eye of the dragon in the Hayabusa village.
In Ninga Gaiden 2, Joe is still recovering from his last encounter. While Ryu fights the Black spider clan in Tokyo, Genshin and a large number of spider ninja attack the Hayabusa village and set the castle of the dragon on fire. Joe waits in the top tower of the castle, protecting the demon statue. Genshin brakes in and engages Joe in a duel to the death.
