Oan, the second planet of Kappa Xi, was the home world of the Oani. The planet consisted largely of water, with numerous islands where the Oani people lived. In 2152, the planet was visited by the Enterprise, only to find that the whole race had been killed by what was initially thought to be a microbe or a form of radiation, but was later discovered to have been a creature made of energy which called itself "Wanderer." (ENT novel: Surak's Soul)