User blog comment:Portgas D.Eros/Zoro and Sanji/@comment-1595565-20101004202739

No, neither Mihawk nor Ivankov has demonstrated either skill with or knowledge of Haki. Besides, it would be less interesting if more people knew it. Fights wouldn't be fun since they could predict the opponents' moves, neutralize any devil fruit, and/or just knock them out with a dirty look. I hope they didn't learn Haki, their current fighting styles are awesome.