In the manga\movie series alternativly called Lone Wolf and Cub, Baby Cart and Shogun's Assassin, Itto Ogami is "the the greatest Samurai in the empire and the shogun's decapitator".
Itto Ogami is a devout Buddhist with a wife and baby boy, who takes the job of decapitating the Shogun's enemies out of a sense of duty. Although he has no ambitions for anything higher, but his enemies in the Yagyu clan resent his success. They frame him as part of a conspiracy against the Shogun. The shogun then sends his ninja spies to kill Ogami, but they end up killing his wife instead. Itto abandons both his life and society in general, becoming a ronin, or masterless Samurai, roving the land, killing anyone for 500 Gold Pieces. He takes his small son, Daigoro Ogami, in the eponymous baby cart, with him, and in between killing people for money, tries to raise his young son.
Itto's greatest goal is to find his way out of the six worlds by finding the reason for the Yagyu's treachery, and getting revenge on them.