The Sky World is the final level, located above the Overworld. In terms of the three terrain types, it is in the top. There is no day or night cycle here.
The Sky World has few terrain types. As it is above ground, the grass is able to be seen, however, it can not be walked upon. Instead, the Player walks on Clouds. There are damaging White Spikes located throughout. The only Biome for this area is Sky.