As a Boy,Ryu Hayabusa lives in the village where his clan has been attacked. His father,who is a Master Ninja,was killed by Doku. He fled as Doku took his Father's blade.
Many Years Later,Ryu trained to be a Ninja Warrior. He infiltrates the Shadow Clan fortress to visit his Uncle,Murai,who explains that Doku was in conspiracy with the Dark Disciple to have his father killed. Ryu stows away on an airship to look for Doku and the Disciple. Arriving at Tairon,Ryu battle against the Fiends and the Black Spider Clan that also seek the Dark Dragon Blade. He meets a Fiend Hunter,Rachel,who also seeks vengeance on Doku for turning her twin sister,Alma into a Fiend.
Ryu faces off with Alma and defeats her in battle. Rachel approaches Alma,but refuses to kill her and is taken by Doku,who prepares to sacrifice her in the ritual to enhance Alma's power. Alma sacrifice herself to save Rachel,destroying Doku's spirit in the process. With his dying breath,Doku casts the blood curse on Ryu,which turns his skin blue and eyes red. The only way to lift the curse is to kill the Clan's Leader,the Holy Vigoor Emperor. Ryu storms the imperial palace,killing the Emperor and lifting the curse. Ryu seizes the Dark Dragon Blade and was confronted by The Dark Disciple,who reveals himself to be Murai. He reveals that his conspiracy to have his Father killed was part of the plan.
Drawing on the Blade,Murai transforms into a devil incarnate and attempts to kill his nephew. Ryu shatters the Blade with the True Dragon Sword and stabs Murai in the heart,killing him. Rachel appears and wished him farewell before Ryu returned to his old village where he honored his father.