"When I was little, my father was famous. He was the greatest Samurai in the empire, and he was the Shogun's decapitator. He cut off the heads of 131 lords. It was a bad time for the empire. The shogun just stayed inside his castle and he never came out. People said his brain was infected by devils. My father would come home to mother each night and he would forget the killings. He wasn't scared of the Shogun, but the Shogun was scared of him. Maybe that was the problem. Then, one night the Shogun sent his ninja spies to our house. They were supposed to kill my father, but they didn't. That was the night everything changed, forever. That was when my father left his samurai life and became a demon. And he took me with him. I don't remember most of this myself. I only remember the Shogun's ninja hunted us wherever we went. And the bodies falling. And the blood." - Diagoro

Astonishingly violent, Shogun Assassin tells the story of Ogami Itto, a powerful and feared Ronin, a 'masterless' Samurai, who once lived a peaceful existence with his wife and his son as the ofiicial executioner for the Shogunate. When he refuses to swear allegiance to Kurando, the most vicious Shogun in Japanese history, Kurando orders the death of Itto's wife, Azame. Blinded by rage, Itto vows to avenge her death, taking his son Daigoro with him on the path of darkness and retribution. They have become Lone Wolf and Cub.

Soon Lone Wolf's sword of vengeance is unleashed upon the evil Shogun's sons and ultimately the legendary 'Masters of Death'!