GreenTengu
Adventurer
The only "only islands" franchise I know well is One Piece.
And one thing that One Piece does extremely well, other than having the clash between a centralized Lawful government against a bunch of Chaotic pirates and even having good and evil elements in both sides that causes clashes....
It is that every single island they land on practically changes the entire genre of the series. They can go from an island in the clouds with winged people and an ancient secret treasure to a spy adventure where the villains are hidden and they have to fight the elite secret agents of the world in a tower to a mobile island hidden in the fog that is filled with zombies and the heroes getting their spirits stolen and put into the bodies of other zombies...
Every single island is basically a whole world unto itself with internal logic that exists only for that particular island, but then you get to the next one and everything can be completely different.
And one thing that One Piece does extremely well, other than having the clash between a centralized Lawful government against a bunch of Chaotic pirates and even having good and evil elements in both sides that causes clashes....
It is that every single island they land on practically changes the entire genre of the series. They can go from an island in the clouds with winged people and an ancient secret treasure to a spy adventure where the villains are hidden and they have to fight the elite secret agents of the world in a tower to a mobile island hidden in the fog that is filled with zombies and the heroes getting their spirits stolen and put into the bodies of other zombies...
Every single island is basically a whole world unto itself with internal logic that exists only for that particular island, but then you get to the next one and everything can be completely different.