oda also loves jrpgs and its a classic trope from dragon quest that the "real" final boss is someone who doesnt show up at all in the first half of the story and only gets vaguely hinted at or implied to exist. imu's a good representation of this bc he's a personification of all the corruption and evil in the world govt.
still i think its possible blackbeard is the "final" final villain anyway. a massive battle vs imu and the government, then one last davy back fight for the fate of the world is how i want it to go at least
Chapter 1062 "City of Emerald"
~ Luffys group see a huge gate that they can get through
~ Luffy tells everyone to hold up as he flings them through the eggshell
~ Franky notices Vegapunk looks like one of the blueprints from Baldimore
~ Vegapunk then starts geeking out about namis climatact, as he thinks it has a DF in it
~ Sanji then speaks up remembering who vegapunk looks similar too, his mother sora
~ The chapter ends with a beautiful double spread with the group of 4 looking over the City of Emerald
~ A haven with advanced technology