User blog comment:AYET/Secondary ability of devil fruit powers/@comment-4830969-20120211062717/@comment-4754162-20120211102852

I am aware Yami Yami no Mi can nullify DF power but as yet was confirmed to be able to absorb power of DF (in which case I think you are referring to the Gura Gura no Mi being stolen, yes?), thus I suppose you are speculating of that being its secondary ability - which I agree too.