The Broken World
Stories tell of the world's ruin five hundred years ago. The story of what happened changes depending on what the source of it is, however they all end the same. The world faced near destruction, leaving only the few parts of habitable land. Each landmass has civilizations that tend to keep within that continent, building and thriving as much as possible within this new world.
An island between all of these continents serves as a trade hub and neutral ground. This convenience has lead to the continents not directly trading with each other. People are only beginning to somewhat seriously travel through to other landmasses as the time before has been spent searching the waters near them.