Anur Phaetos is a gas giant world populated largely by a species known as the Ectonurites. The planet's dense gasses and atmosphere don't allow any sunlight to get through. How Ectonurites traverse their dark world is via a glowing mineral known as corrodium.
For the longest time the Ectonurites were an isolated and closed off race, until the Galvans produced a sort of solar shielding cloak which allowed the race to travel beyond their dark world and easily become a space faring race.
However in recent year, the Jupiter Empire carrying solar weaponry that could penetrate the Ectonurite's "Armor" came to the world, forcing the leader the Ectonurites into a deal. The planet would be counted among the Empire's ranks but be mostly left alone, so long as the Ectonurites provided the planet's corrodium.