After defeating the monster for the final time, Ryu bemoans Irene's passing. However Irene is killed when her soul is sucked away by the awakened Sword of Chaos, and Ryu has to fight the revitalized and transformed Jaquio again. He discovers her kidnapper is the Jaquio, and defeats him again. Leaving her in the care of Robert, Ryu returns to find she has been taken away again. He defeats Ashtar there, but is told by Irene to go destroy an altar. He is saved by Robert, and follows Ashtar into the Maze of Darkness. He fights through the hordes of tribesmen from the world of chaos, and gets ambushed by Ashtar. In Ninja Gaiden II: The Dark Sword of Chaos, Ryu is informed by Robert to go into the Tower of Lahja and rescue Irene. He defeats Clancy several times - each form more powerful than the previous one - and stops him from carrying out his vendetta on the world. Ryu follows Clancy into the subspace to stop him. Ryu is miffed when Clancy reveals his evil plot to gain control of the Life Energy used to create BIO-NOIDs. Although Ryu loses to his double on the first meeting, he eventually defeats him in front of Foster, effectively removing the latter's power base. There he encounters Foster and the BIO-NOIDs, including his Doppelganger. He investigates her last known location and is met by Clancy who leads him to the Castle Rock fortress. In Ninja Gaiden III: The Ancient Ship of Doom, Irene goes missing in action, and Ryu is suspected of her murder. However he manages to banish the Demon as well as winning the love of the CIA agent, Irene Lew. He defeats the Jaquio as well but is too late to stop the Demon from awakening. Arriving in the Amazon Rainforest, he defeats the Jaquio's minions and his brainwashed father standing in his way. He learns of the story behind the Light and Shadow demon statues from the archaeologist, Doctor Walter Smith, and is coerced by Foster to stop the Jaquio's plot of bringing back the Demon with the statues. In the first NES game, Ninja Gaiden, Ryu goes off to America to investigate the disappearance of his father.

His father, the leader of the clan, Jô Hayabusa, has entrusted him with the family heirloom, the Dragon Sword, which is forged from the fang of a Dragon. He is a young member of the Dragon Ninja clan, whose duty is to uphold peace and to battle evil.

Ryu Hayabusa, the protagonist, is known here as the Ninja Dragon. The NES trilogy chronicles how Ryu and Irene meet up, and their conflicts with the Jaquio, Ashtar, and rogue elements of the CIA.

Ninja gaiden spear girl