In Satan's Sword III: The Final Chapter, Ryunosuke is on a journey to fulfill a promise he made to a dying friend - to return his sword to its rightful owner. Disguised as a beggar monk, Ryunosuke faces several challenges along the way. When he is harassed by the members of a country dojo or fencing school malingering outside their fencing hall, Ryunosuke must use his sword skills to defend himself.
However, the members of the dojo are not easily deterred, and they continue to taunt and harass Ryunosuke. As he continues on his journey, Ryunosuke also encounters other swordsmen and bandits who seek to challenge him.
As Ryunosuke gets closer to his destination, he realizes that his journey is not just about returning the sword but also about coming to terms with his past and the violence that has consumed him. The final showdown between Ryunosuke and his enemies serves as a climactic and fitting conclusion to the Satan's Sword trilogy.
