Gravity always wins. The world is in constant flow. Where ever you
are, you are always on a hill, and there is always a slope. And it is
always raining. Welcome to Riask.
The Shape of the world

Riask
is neither a round world nor a flat one. Its surface is shaped
something like a funnel. The closer to the center one gets, the steeper
the ground is, and all water flows to the central ocean. This ocean
isn't emptied by anything so mundane as evaporation -- There is some
sort of portal effect that drains the ocean into the sky. Sages claim
that its not actually a portal and its just the way the world is shaped,
but eventually just throw up their hands and settle for people calling
it a portal.
Riask's
ocean dumps directly into one of its two suns. The suns are small and
similar to those one would find on a flat world-- glowing balls of heat
and light with no discernible source of power. The first sun vaporizes
the incoming oceans, complete with its dirt, fish, and anything else
that may be in it, and form Riask's cloud cover. Riask's weather is
mostly about variations on constant light rain. In fact, it doesn't have
a day-night cycle either: just perpetual overcast skies and
temperatures that fluctuate based on cloud cover.
Riask
seems to be surrounded on all sides by solid stone. Sages are not sure
if this is just the way the void makes itself manifest, or if the stone
actually exists. Those who deal with it, usually under a lot of silt,
know that its quite hard, but can be mined, and doesn't pull any silly
tricks like reforming after its dug at least not on any time scale that
matters.
The funnel and the suns create five grand weather zones on Riask: Ice, Spring, Tropical, Waterfall, and Ocean.
The Magic

Riask is the home and center of
Vasic Stone Magic.
The stones themselves are cut from the foundation of Riask itself --
the black substance is considered by them to be the foundation of the
universe. Getting the stone is not easy: the stone is very hard, and in
most places found only under a thick layer of sediment and water.
Riask's water table is quite high, and the only places where it is
naturally exposed are on the cliffs of the waterfall zone.
Vasic Stone Magic includes teleportation. This is core to what Riask is, and prevents transportation from bogging down in the pouring rain and perpetual slopes.Vasic magic touches every part of the civilization of Riask.
Other kinds of magic don't work as well in Riask, though
The People
Riask is fairly densely populated, at least in its center -- its a relatively small world with not that much living space. The great cities of Riask are almost all located in the waterfall zone, where the foundation stone is exposed and transportation via Vasic magic (both in world and off world) is cheap. The summer zone is also densely populated with food growers (especially rice), though civilization trails off in the spring zone. Goverment types also vary by zone: the great cities tend to have councils elected by those above a certain wealth line, while the summer and spring zones have a more feudal build. Riask is not politically unified, but it does have a certain cultural cohesion.
Riask is mostly inhabited by humans. They've come to riask in several waves, and have made themselves at home. Other species can be found in its great cities, but the country side is overwhelmingly inhabited by humans and the local Mugraggle. The Mugraggle are thin, spindly humanoids at home wading in water. They don't handle dim or bright lights well at all
Mugraggle [0]: terrain adaptation (Mud, halved effect-50%) [3], Night Blindness (Mugraggle +0%) [-10], breath holding x2 [2], +1 swimming move [5], night vision 1 (brightness penalties) [0]
Murgraggle night blindness doubles the -1 from full day light as well as darkness penalties. On Riask, this is a much smaller problem, as the amount of daylight is constant. Campaigns set solely on riask may halve the cost of this disadvantage. Mugraggle form approximately 30% of the population of Riask. They are generally lower class, though some have risen to high rank, particularly among their own people.
Fauna
Riask is an ideal home for amphibians, and they abound, from giant crocodilian forms to near-fish to grazers and burrowers. Its also home to a number of aquatic mammals, and a abundance of freshwater crustaceans and snails -- the moist climate is friendly to gilled invertebrates. Flying creatures are rare, at least on the floor of riask -- the ceiling (watered by dew rather than rain) is said to have an abundance of creatures.
More is coming
I hope you've enjoyed Riask so far -- but this is just the start. Riask is the 'default homeworld' for the refuges setting, as it has fairly cheap transportation to other worlds. You'll see a good deal more of this world. Also, this was the original setting Vasic magic was designed for, so all of that information is already out there. Welcome to Riask!