Onserf is a frigid L class world within the Etile system. It is named after the Sreppari word for "liquid gas" because of its lakes and rivers of liquid nitrogen.
The planet has an atmosphere of nitrogen, and a strong magnetosphere, keeping it very safe and inert from the radiation of space. The planets surface is covered in various forms of water ice and rock, which is easily weathered away by the thick atmosphere and rivers of liquid nitrogen, so the surface contains little mountains or variation. Around the surface are small lakes and rivers of liquid nitrogen, connected together through a "nitrogen cycle".
The planet is extremely cold, similar to Titan before terraforming, but this allows a complex ecosystem of nitrogen to form. The thick atmosphere is 99.999% nitrogen, which can condense into droplets and rain down onto the planet in thick sheets of liquid nitrogen. This creates a stormy, frozen environment of nitrogen that creates many puddles and ponds of liquid nitrogen, which shortly after evaporates back into the atmosphere to repeat the cycle again. Cryovolcanoes sometimes spew volatile ices from deep within, sometimes reaching space.