User blog comment:JustSomeDude.../Why Zou?/@comment-24769684-20151208132848/@comment-4899461-20151208150823

Probably him being overconfident in his plans to win in Dressrosa. Law was his real prize in 730, since he was defeated and an easy catch. Doffy wounded Kine'mon in 730, and he didn't really go down, it would have been a longer fight than Doffy wanted. It also sounds like of the 4 samurai, Momo is the one that Kaido/Doffy are the most interested in.