yo!
i don't see anything about it, so maybe i'll be first for this guess ^^.
Check OP 464 anime, at about 20-22min, doflamingo gives to oars jr. pretty clean cut. And a big one too, without using any swords.
So, i'll say that its THIS particular shichi, who messed some things up on this island. Also, they never met him before, so i guess it will be him to fight strawhats on this island
That would be nice, i hate that guy