Ryu Hayabusa is a modern day ninja. He is the leader of his ninja clan which draws from the magical powers of ancient dragons. He carries the "Dragon Sword," a powerful and ancient weapon passed down to him by his father. As well as wielding the Dragon Sword, he must also protect the Dark Dragon Blade, a sword that seals the souls of dragons which, if released, could create havoc on Earth. He is the protagonist of the Ninja Gaiden games, as well as a character in several Dead or Alive games.
Ryu Hayabusa was born the son of Joe Hayabusa, a powerful and skilled ninja and leader of the Hayabusa ninja clan. Ryu went through vigorous training as a child so he could perfect the ninja arts and become a deadly warrior with time.
Ryu's first real test came when he was 18 and ventured off on his own to stop a cult in America from summoning a Devil King to prove himself to his father. After successfully stopping the cult by taking out their leader, a descendant of Nostradamus, Ryu's mission was complete. One year later, however, Ryu again had to travel back to America to defeat a crazed dictator who had overtaken New York City. He successfully felled the dictator and his allies and promptly returned to Japan.
Two years later Ryu was entrusted with the Dragon Sword when his father, the original owner, went off to train in the wilderness. Soon Ryu is summoned to visit his uncle at the Shadow Ninja Fortress, and after killing several attackers to meet his uncle finds out that his village is burning. Ryu returned to his village to find it under attack by Doku, a demon who he is unable to defeat and quickly vanishes. After seeing his friends and family die, Ryu sets off to find and destroy Doku. Eventually his path pits him against a supreme deity named Vigoor, who controls the power of the Dark Dragon Blade. After defeating Doku in combat, a curse is placed on Ryu, but he continues fighting and eventually defeats Vigoor.
Some of Ryu's other encounters include teaming up with the CIA to defeat a resurrected dark god, and even fighting vampires.