The map reminds me a little of the world in Hunter x Hunter. The viewer is initially shown a world map (a flat projection) that is basically the typical cluster of continents in a vaguely ring-like shape, but it is much later revealed that it’s not a map of the whole planet but just a fraction of the surface area, and all the inhabited continents are actually completely encircled by one giant super-continent labeled “The Dark Continent”, meaning every known ocean was just part of one super-continental lake called “Lake Mobius”.

p.s. watch/read hunter x hunter, it’s a cool manga