User blog comment:JustSomeDude.../Stray Observations from 760/@comment-4830337-20140910230804

CP0 obeys Doflamingo because he is still a World Noble. Doflamingo is not affiliated with the other World Nobles, but he still has the title, since he was born in it, and even if the other World Nobles don't recognize him as one of their own, the World Government and CP0 still recognize him as a World Noble.

I'm a bit curious on what Doflamingo means by having one of the rarest powers in the world. Does he means having a Devil Fruit ability, being a World Noble, Haoshoku Haki, or perhaps something else?