Realm of Silt
Ulmenus is a beautiful realm of babbling creeks, vast rivers, and lush wetlands. At the heart of its sole supercontinent sits the Crying Mountain and its countless rain-fed waterfalls. Here every waterway in the Realm of Silt finds its origin. Eventually finding their end in an immense life-filled bog that empties into the ocean surrounding the continent. Life in the native biosphere is adapted to a semiaquatic existance and mirror the stages of the world's water cycle. Bringing Primal Earth and Water towards a seamless unity on its path from the mountain rains to be dispersed into the Still Ocean.
The single continent on Ulmenus, known as Ulmek, is fairly circular in shape. At it's center is a massive mountain that collects clouds to feed it's many rivers. These rivers, some of which that are as wide as seas, travel throughout the realm until you reach the Boglands. The Boglands are massive and surround the continent as a boundary between land and the sea.
Constant rain leads from the ocean to the mountain from all sides.
Three groups of River Manfolk. One set of Mountain Manfolk. Four sets of Bog Manfolk. One set of Ocean Manfolk. There are also frog-like sophonts and toad-like sophonts in the Boglands. There are slimy-skinned, nearly faceless sophonts that ride up and down the rivers with magic. Catfish Sophont that use the River as a bartering tool.
Each section of Ulmenus has a unique set of flora. The mountains have a few great trees, but mainly strong root plants to survive the rain. Then the rivers give tons of room for forests to grow alongside bushes, grasses, and so forth. Then the boglands can be simple swamps to vibrant, water-logged jungles. The ocean has no plantlife.
Certain fish are brought by the rain to the mountains and reach maturity by the time they reach the Boglands. They breed, sending eggs into the ocean, and then die. There are also lots of river creatures of course.
Glow can only be extracted from the "pristine" parts of the river, in other words closer to the mountain. Primal Water is found in the rain while Primal Earth must be mined from the mountain.
Lots of boat tech. A lot of weather manipulating/using tech like rainmills, windmills, and watermills. Steel is made in the mountains.