One Piece Chapter 33, page 5: The Silent Man

Sham and Buchi slash forward with a loud "SHAAAAAA...!!" but their claws strike only empty air. In the blink of an eye, Kuro has vanished, reappearing silently behind them. "Who did you say... you were going to kill?" Kuro asks coldly. The Nyaban Brothers freeze, sweat pouring down their faces in sheer terror. Jango is stunned, wondering when Kuro managed to get behind them, while Usopp gasps, "Ah... It's.. It's the 'Silent Step'!!" Zoro watches closely, noting, "What a weird looking weapon..."