Nother/Frontier
Frontier (Lunar: Vienĉing 'border star', Thalassarctian: Báḱfikeín̂n̂i 'on a faraway border') is an extrasolar planet. It was one of the first planets colonized by Humans and Lunars at some point after the development of faster-than-light travel in the 24th century.
At the time of colonization, Frontier had one indigenous intelligent species, the icebears; it is as yet uncertain as to whether they are in fact native to the planet, or if they are ultimately from Earth or one of its colonies, and had arrived earlier due to a timeslip effect. The icebears went extinct in the middle of the 28th century with the death of the last surviving member of the species, Táq Uĺurít́uq.
There are two notable characteristics of Frontier. First off, that the overwhelming majority of the planet's surface is ocean: the largest continent and site of the major Earth colony is only 382 heng squared (~100,000 km², about the size of Kentucky or South Korea); besides this, most settlement is on ships or on stabilized sea ice. Secondly, neither stars nor sun are visible from the planet's surface. The icebears attribute this to the actions of the legendary king Báḱfikeín̂n̂i, who brought darkness to the world to protect it from a supernatural threat; for him the planet is named.