End of Sword Master Iron:
There was a rumor that at the time of his fight, he didn't even have a living body! Supposedly, he was able to learn the reflection technique only after offering his body in exchange!
Duelist Kaien had an unofficial duel with Iron. He wouldn't confirm or deny this rumor, but he said, "If you ever need to fight him, use Triple Slash and Hammer Crush." I think he might have been onto something...