User blog comment:Reflected void/Devil Fruit Power Transfer (a theory)/@comment-4754162-20120801155730/@comment-1405658-20120801160612

You make a good point, if the Yami Yami no Mi's "Gravity" affects Devil Fruits, it could be what allowed him to designate himself as the next host by pulling it in. Or, the the other theory from the unnamed contributor, that it "absorbs" them to negate the power, and it can be stolen if they are dead.