The theme of Mariejois is like Olympus in Greek mythology because they are both located in high altitude place and has a gigantic palace which is built on top of the mountain. (Mariejois built on top of the Red Line.)
Olympus is the home of divine family and ruling gods and Mariejois is the home of Celestial Dragons which we can say the divine family in OP and Gorosei the so called gods.
The pattern or theme of Mariejois is Olympus so we might see a character which is conceptualize and inspired by the king of gods in Olympia. Who’s the king of gods and ruler of Olympus?
In ancient Greece Zeus is the king of gods, god of sky and ruler of Olympus, he is the strongest god in Olympus and no one can oppose him nor fight him because of his great power.
A character inspired by Zeus is very possible because there are gods in One Piece and maybe that strongest god will be the final villain that Strawhats will going to face in the final war against Marines, World Government, Celestial Dragons and Gorosei in the Mariejois.
Remember what Oda said before that the Marineford war will gonna look like nothing in the final chapter that’s why he’s motivated to keep drawing One Piece and he likes his fans to stick with him til the end.
Luffy’s Grand Fleet and maybe other pirates or all pirates and Revos will join Strawhats in the huge war against World Government, Marines, Celestial Dragon and Gods in Mariejois, this is great to see as the last chapter of One Piece!
Mariejois is the greatest place for the final war because remember the impact, excitement and insanity that we felt when Whitebeard Pirates attacked the based of marines in Marineford and started the summit war, what more if we see the Strawhats and his allied forces attack the Marines, World Government, Gorosei and Celestial Dragons in Mariejois and start the final great war. It will definitely give us more excitement, goose bumps and emotions because many pirates and marines will die in this war.
*Theory by Fire_Fist_Recca
Rob Lucci ?
Lucci is pretty sure to join their alliance since the CP9 are now considered pirates and are being hunted by the World Government.