Maybe Buggy is the true final villain and just played the fodder. Like in Saw 1, Jigsaw lying in the same room playing dead, but in the end being revealed as being the mastermind.
Buggy portrays himself as the fodder, but is seemingly always able to catch up to the rest. Getting into Impel Down, being freed and, just as Blackbeard, taking Prisoners with him as subordinates, joins the Marineford war, becomes Shichibukai and now Yonko.
He planned everything.