The Chiss and baseline Humans regarded each other as aliens, but genetic studies have indicated that the two peoples were close biological cousins, and it is not clear whether the differences between them were the product of straightforward evolutionary divergence and differing planetary habitats, or the result of genetic engineering similar to that which produced such hybrid species as the Massassi, and the Myke.
Due to the remote position of their home territory in the Chiss Ascendancy they remained largely an enigma to the rest of the galaxy, and contact with outsiders was limited even in the days of the Galactic Alliance. The Chiss were a tall, blue-skinned Near-Human civilization from the Unknown Regions, best known as the people to which Grand Admiral Thrawn belonged.
