Eseldai

Eseldai is a world almost entirely engulfed by water, with floating and underwater cities (engineered with magical pockets of air) ruled over by a monarchy, and several other human governments.   When Eseldai fell to a disastrous great flood, the High Division of Magic (HDM) pulled together and formed the Falcrum to aid the helpless, eventually travelling to different realms to find homes for the people, linking them all back to the Falcrum, creating an inter-dimensional network. These realms are all ruled by a separate government of their own race, though all power is mostly run back through the merfolkian empire.   The Falcrum is almost as big as a world itself, a travel network, a social hub, and a magical tether that holds realms together. There are a few cities here, however the main city is called Sireline, the working class and such only pass through, the only ones actually liable to afford this place are the higher class/nobles/criminals.