Plot
Long before the civilization of mankind, extemely fierce yet primitive life forms battled for supremacy. Thousands of years ago, the final battle took place.

One side, while using all of its strength, perished while the other was sent to and sealed off in a different dimension. The tale of this battle was preserved in legend after mankind began to populate the earth and the two forces, known respectively as the gods of Dragon and the demons of Darkness, came to be revered by certain clans among the people.

By the summer of A.D. 1989, even this ancient tale had almost been completely forgotten. However, one evil being schemed to bring back the gods, and he amassed many followers and began to build an empire of darkness.

That being was the Jaquio- a member of the Demon clan who plotted to bring the demons of Darkness back to earth. He secretly schemed to steal and bring together, for the first time in aeons, the two "Statues of Light and Darkness" said to contain great magical power.

This would open the passageway between dimensions and allow the demons to escape into our realm.

There was, however, one man who would stop at nothing to foil Jaquio's plans- head of the Dragon clan, Ken Hayabusa. After entrusting the Dragon Sword, an heirloom of the family and clan so old no one knew when it had been made, to his son Ryu, Ken left for the fateful battle against darkness.

Unfortunately, Ken was defeated by Bloody Malth, a member of the Malice Four, Jaquio's most trusted minions. After his defeat, the Statue he was protecting fell into the hands of Jaquio. After reading his father's last will and testament, Ryu took the Dragon sword and journeyed to America, determined to avenge his father's death.

After vanquishing one member of the Malice Four, Barbarian, Ryu encountered a mysterious lady named Irene Lew, who was a CIA operative. She entrusted one of the demon statues in Ryu's care, and vanished. Ryu quickly made his was across the mountains to visit a man named Dr. Smith, a trusted associate of his father.

It was there he learned the origin of the demon statues and the damage they could cause. Before he could learn more, one of Jaquio's assassins took the life of Dr. Smith, and Ryu was accosted by members of the CIA. Ryu was taken to the CIA headquarters and briefed by a man known only as Agent Foster.

Foster told Ryu of the CIA's desire for obtaining the demon statues before Jaquio could unleash their true powers. Ryu made his way to the ancient ruins Jaquio was residing in, and was forced to relinquish the demon statues in exchange for Irene's safety.

Ryu valiantly fought his way back up the tower, and encounted Bloody Malth, the man who killed his father. From Malth Ryu learned that his father was not really dead after all. Ryu rushed up the ruins and finally got to face Jaquio. Ryu was stunned to find out that what Malth had said was true, and Ryu was forced to fight his father who was under the control of Jaquio.

Ryu destroyed the device Jaquio was using to control his father. The father and son reunion was brief, as Jaquio fired an energy blast at Ryu, but Ken Hayabusa jumped in front of it and intercepted it. Vowing to get revenge once and for all, Ryu fought Jaquio in mortal combat and was victorious.

Unfortunately, Ryu had failed to notice the demon statues, and when an eclipse occured the demon statues unleashed a horrible demon that Ryu had to face. Only his cunning and the power of the Dragon sword saved him from the demon, and vanquished the evil.

Irene and Ryu fled from the crumbling ruins. As they watched the tower crumble, Foster contacted Irene via a communication link and told her to kill Ryu Hayabusa and get the demon statues.

Irene could not bring herself to do this, and Ryu vowed to get revenge on Foster for setting him up eventually. But for the moment, Irene and Ryu watched the sunset as they thanked the gods for delivering through the tough ordeal.

Watching this duel from afar was the real evil, the head of the Demon clan, the evil lord himself, Ashtar. As it turned out, Jaquio was nothing more than a pawn for the greater power. Ashtar hid himself in the darkness, assessing his enemy.

His eyes shined and he licked his lips. He had only to wait for his enemy. A year had passed since Jaquio had fallen, and Irene Lew was fronting an investigation to find the location of Ashtar, when she vanished.

A member of a secret CIA force created to destroy Ashtar, Robert Sturgeon, came into contact with Ryu Hayabusa while he was searching for Irene. Robert told Ryu where Irene had been taken, and Ryu journeyed to the Tower of Lajah, where the CIA force was pinned down by Ashtar. The situation looked desperate.

At this point, Ashtar, who himself had actually seen the birth of the Dragon sword and knew of its potentially awesome powers, emerged again from the depths of his dark realm. Ryu, who knew nothing of all this, was in grave danger as Ashtar used his black magic to nearly destroy him and Irene.

Ashtar wounded Irene, and Ryu, overcome with rage, pursued Ashtar through a twisted realm created by Ashtar known as the Maze Of Darkness. An epic battle ensued, and Ryu summoned all of his courage and skill to destroy Ashtar.

But the quest was far from over. Ryu ventured on, into a dark tower filled with many demons. After finally braving his way through it, Ryu discovered that Jaquio had been reborn, and he was more powerful than ever before.

After Ryu delivered the fatal blow, he rescued Irene and prepared to leave the tower, but he failed to notice that the blood of the Jaquio had touched to blade of the sword of Darkness, opening the doorway between worlds once again.

Jaquio was transformed into a horrible demon, and Ryu had to destroy him once again. After the battle ensued, Ryu was victorious. He and Irene fled the dark tower before it could collapse upon them.

Unfortunately, Irene had suffered many wounds and had passed on. Overcome with sadness, Ryu proclaimed that he would do anything to have Irene back. Hearing his plea, the essence of the Dragon sword granted life back to Irene, and vanished.

Overcome with hapiness to have Irene back, but secretly afraid that he would run into trouble without the Dragon sword to protect him, Ryu wasn't sure if this was a real victory or not. He only hoped that he wouldn't have to battle the forces of evil ever again.

Unfortunately, peace and Ryu Hayabusa do not go together well, and it was only a matter of time before he would have to fight again. Irene Lew was assigned to a mission to investigate a series of experiments going on in the Castle Rock Fortress, and was killed while on duty.

Once an investigation ensued, the murdered of Irene Lew was found to be Ryu Hayabusa himself. Pursued by the law and out for vengence, Ryu Hayabusa must now set out on a quest to prove himself innocent and bring the true killer of Irene Lew to justice in the final chapter of the Ninja Gaiden saga.