One Piece 4x119
Secret of Powerful Swordplay! Ability to Cut Steel and the Rhythm Things Have!
While Miss. Doublefinger's fight with Nami was challenging, Zoro is having an even more difficult time fighting Mr.1: A man who can change his entire body into steel - something that Zoro cannot cut. As Zoro nears death, he must discover the secret to "the breath of all things".