Buyan

A mysterious island that arbitrarily vanishes from and reappears on the surface of the Endless Blue; atop its surface is its own minature civilization. In truth, the "island" is the back of an intelligent, and benign supermassive sea creature whose life is tied to that of the planet's. It sees itself as a guardian of its occupants, and its occupants a salve for the loneliness caused by being a singular existence. "Buyan" is the name given to the creature itself as well. Occupants of Buyan are amphibious, and when they pass on, they are transported by Buyan to the Maw. 

Buyan is named for the fantastical location of the same name.