From Introduction:
East of the Province of the Red-Gloved Daimyo, well within the lawless lands, there is a region that is home to the so-called boat people, who live along the coast and on the vast river deltas in that area. Rather than settle in regular cities - which would be hard to build in this swampy part of the country anyway - these descendants of Coroan slaves live on boats and floating platforms. They live by fishing and by diving for the fantastic treasures hidden in the half-sunken Imperial temples littering the coastline and the swamps.
While they are a cheerful and happy people, their live is not easy at all due to the many terrors that prey upon man just below the waterline and the shapechangers that stalk the jungles.