While fighting Monet, a Logia user, on Punk Hazard , Zoro was able to slash her on the cheek, displaying the use of Busoshoku Haki , after saving Tashigi .  Being his personal Haki specialty, Zoro has extraordinary mastery of Busoshoku Haki.  During the Dressrosa Arc, it is revealed that Mihawk taught Zoro how to imbue his swords with Haki .  He can imbue Busoshoku Haki into all three of his swords at once; in doing so, he managed to cut down Pica , who had already covered his entire body with the same Haki, thereby also demonstrating his supreme mastery over Haki as compared to the Donquixote top executive.  In the film Gold, Zoro was able to reinforced his arms with Haki to successfully defend simultaneous slashes from both his swords Sandai Kitetsu and Shusui without getting injured at all.
Toei Animation's version makes use of four pieces of theme music : one opening theme and three ending themes. The opening theme is "Believe" by Folder5 .  The ending themes are "Run! Run! Run!" by Maki Otsuki for episode 63,  "Watashi ga Iru Yo" ( 私がいるよ , lit. "I Am Right Here!") by Tomato Cube until episode 73,  and "Shouchi no Suke" ( しょうちのすけ , lit. "That's a Fact!") by Shōjo Suitei for the rest of the season.  4Kids Entertainment used original theme music in their adaptation,  while Funimation Entertainment opted for English language versions of the theme music pieces used by Toei Animation.