Kathoon is a world in perpetual darkness due to it being continually in the shadow of its moon. In a normal system, the planet and moon orbit about their common center of gravity. It is unknown why this situation is not present in this case. The planet was settled by humans who developed artificial lighting. The people of the planet over time developed eye sight adapted to the darkness of the planet.
In the absence of sunlight, Kathoon is heated geothermally. Kathoonians in general have no special abilities.