Man-Slashing Horse-Piercing Sword

From nothing comes a King

In medieval Japan, a brutal and corrupt magistrate is planning to kill the child who is about to become the heir to the estate and position of the local lord and substitute his own "heir", an orphan, in order to get control of the late lord's estate and rule as the impostor's "regent". However, a mysterious stranger appears and sets out to thwart the magistrate's plans and free the people from his oppressive rule.