User blog comment:Manuel de la Fuente/Kaido revealed 12 years ago?/@comment-5690257-20150731110412/@comment-5774380-20150731121127

It would be very strange that Oda had created two characters in villanious role with horns, long hair and spiky bracelets and they turned out to have no connection at all, don't you think?

The early design of Kaido's face doesn't interfere with this theory, because the face of that guy from Color Walk 2 is not even visible. The final design of Kaido actually looks like a mixture between both previous versions.