PathFinder are Humans that have been genetically modified for space travel. This has resulted in a red-haired, light-skinned with blue sheen Caucasian tribe. The PathFinders were genetically modified to have gills (though not all PathFinders have gills anymore) so that they could use the water-filled hibernation pods on (their spacecraft) the PathFinder which allowed them to travel the interstellar distances required by their mission to find alien life.
After hundreds of years they came back to their home world, but there a thousand of years have passed by. The people on their home planet thought they were aliens because the fact that Humans had gone to space had long been forgotten. The PathFinders were imprisoned to be released years after, isolated and discriminated in a small village.