Kojiro is a legendary Straw Hat ronin and the final opponent of the Mythic Tale The Six Blades of Kojiro. He and five chosen Straw Hats swear to kill Jin. You must beat the five before Kojiro will face you in a waterfall cave near Omi Monastery.
The musician Yamato tells Jin about the challenge. Each of the five followers waits at a different duel site around the island. Once all five are dead, Kojiro's location opens up behind a waterfall at Omi Monastery.
Jin asks whether the armour really was blessed by demons, and Kojiro answers with a question. During the fight Kojiro boasts of a thousand kills. Near the end he asks whether Jin is the one who will finally kill him. Jin wins and ends his rampage.
Hirotsune
Hirotsune is one of Kojiro's five Straw Hat followers in The Six Blades of Kojiro. He practises with his sword in the Field of the Equinox Flower while waiting for the Duel Among Spider Lilies.
Kanetomo
Kanetomo is the cruellest of Kojiro's five Straw Hat followers in The Six Blades of Kojiro. He waits for Jin in Kubara and kills peasants to pass the time before the Duel Under Autumn Leaves.
Kiyochika
Kiyochika is one of Kojiro's five Straw Hat followers in The Six Blades of Kojiro. He meditates under a waterfall near Lucky Genzo's Inn while he waits for the Duel Under Falling Water.
Tomotsugu
Tomotsugu is one of Kojiro's five Straw Hat followers in The Six Blades of Kojiro. You find him fishing on a beach near Urashima's Village, ready for the Duel of Crashing Waves.