The protagonist, Kurogane Yaiba, is a samurai wild child who trains in the jungle with his father, Kenjurou. By a twist of fate, the determined samurai, Yaiba, returns to Japan and encounters his rival, Onimaru Takeshi. Yaiba, who lives for serious battles, embarks on a spectacular adventure when Onimaru obtains the "Legendary Demon Sword!" (Source: Shogakukan, edited)