User blog comment:Lordxehanort/Speculation and Opinions/@comment-1365956-20100202230111

Maybe it was Blackbeard. He may have had Shiryuu give the order so he could see who fate would side with. Or maybe it was Doflamingo. He could have used his abilities to manipulate a soldier into opening it for him, in order for him to make the outcome of the new era more interesting. But I'm just guessing.