Vivi will rejoin the Straw Hat Pirates as a permanent member
Nefertari Vivi is the princess of the Alabasta Kingdom. Vivi traveled with and assisted the Straw Hat Pirates for almost the entire Alabasta Saga and strongly considered joining their crew after Crocodile‘s defeat. Though she ultimately declined their offer in favor of working to restore her country, she remains closer to the Straw Hats than anyone else outside of their crew. She and Karoo are now regarded as honorary members of the Straw Hat Pirates, at least by Luffy and the others.
I’ve thought for a while that Vivi would be joining the crew. Now it’s looking more and more likely. Chapter 1085 seems to finally confirm Vivi’s entry into the crew: Cobra Nefertari in fact gave Sabo the task of revealing to his daughter and Luffy the fact that the Nefertari Family is part of the D Clan, and consequently Vivi could also have inherited the Will of D. This revelation now becomes fundamental for the development of the story, as it makes Vivi one of the characters destined to put an end to the World Government and not to make Cobra’s sacrifice in vain.
It wouldn’t make sense for Vivi to return Alabasta given that CP0 is on her tail and we were given confirmation they want to make her disappear. This would imply the World Government is going to do a regime change in Alabasta. They will choose a new royal family that would be subservient to them.
At this point Vivi will have to join Luffy‘s crew: discovering the truth about the Void Century, about the D. and the creation of the world as it is known in One Piece will be imperative, and the only way to obtain all this knowledge is to reach Laugh Tale together with Luffy.