Zeroth is a planet almost completely covered in tundra, due to the fact that it is many, many light-years away from the supergiant star it orbits, Rigg. It is one of seven thousand planets to orbit the massive star, and is one of the farthest away from it.
Zeroth is very, very, very cold. It has no oceans, for all the water on the planet is frozen. The landscape is composed of windswept, barren tundra with no trees or other plant life. The only other landscape is spiky, barren mountains.
Zeroth has, by sheer coincidence, has been nicknamed Siberia by its inhabitants, not because of its resemblance to the very cold country on Earth, but because that was the name of the small, fluffy dog of whoever came up with it.
The only civilization on Zeroth is sparse, small towns and other minimalistic settlements. However, there are also very large war bases on Zeroth. The planet is, thus, used mostly as a Foo war outpost.