User blog comment:Don7/Law's ulterior motives/@comment-5387880-20130130155434/@comment-5387880-20130130162149

Anoter theory hit my head just now : If he keeps being a schibucai = Law will make Kaido angry with Dofla and Kaido will want to kill Dofla. Then the only way for Dofla to survive and defeat Kaido is to join the alliance of Law-Luffy.

I prefer this theory over everything, just imagine a triple alliance of Doflamingo-Law-Luffy against Kaido and his army of Zoans.  DAMN EPIC!