User blog comment:Kaido King of the Beasts/Chapter 937: Starving for Action (and Shiruko)/@comment-25654036-20190322111027/@comment-2600:6C5D:5D00:1C9:A462:7D29:DCB0:CF64-20190323025255

It could be the same regarding Zeff. The people say that he earned is nickname "Red-Foot" due to his kicking style while stained by the blood of his foes.