In their final clash, Zoro was using Haki and a named attack. Killer wasn't.
Actually Zoro never used Haki in this exchange. That was just Killer's blood on Zoro's sword. The official coloring of that attack is out.... Click the link and scroll all the way down.
https://one-piece.com/news/detail/20201111_11715.html
In their final clash, Zoro was using Haki and a named attack. Killer wasn't.
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https://one-piece.com/news/detail/20201111_11715.html