All these end-game lore discussions make me think about the treasure of Marie Joa that Doflamingo mentioned. Obviously, it will be brought up again in the future, but what the hell could it be?
How much does Doflamingo know in general?
Was he simply referring to the MotherFlame / ancient weapon? But to be able to control the entire world itself, just by that alone, is doubtful. And why did he need the op op no mi to begin with? Man, this chapter strongly raises my curiosity about past chapters as well.
Not to mention the tontatta tribe that helped in the war, they have a long history with the Donquixote Family that dates back 900 years ago.
Oda..left us all with more questions than answers.