Corpse-Marrow Fens

These marshes formed where plague pits, battle dead, and necromantic runoff combined over generations. Reeds grow in pale knots around bones below the waterline. Fog takes lantern light too easily. Ferries run by undead labor are common because the living do not like poling the deepest channels at night. The fens are dangerous but economically important: they preserve canals, reeds, medicinal bog salts, and hidden routes that no cavalry can follow.