The Floodsea is the world.
It wasn't always. Before the Flood, green and brown dominated the landscape. Deserts and forests, mountains and plains. But as the rains fell, as the water grew higher, the sands and the trees and the grasses were swallowed by a ravenous ocean whose warnings few had acknowledged. Now, the tallest mountain ranges stubbornly poke their summits above the lapping tides, but the Floodsea, as the single ocean is known, is patient. The Floodsea will remain. Can the mountains say the same?
It's impossible to travel the Drowned Shores and escape a view of the Floodsea. Dark and endless, it is a constant reminder either of humanity's tenacity and willingness to survive, or of the Flood and its eventual return. Its waves tap against the Shores, lightly in some spots, aggressively in others. Farther out, the water is more unpredictable.
Some sea nomads have made attempts to map the Floodsea, marking its deepest points, its roughest waves, its fresher outlets. But in the end, the Floodsea is too vast, and the nomads and pirates both have trouble--and reluctance--in communicating their findings, the way they understand the water. And so, for most of the denizens of the Shores, the Floodsea remains a mystery, comforting in its consistent incomprehensibility.