A Delta Quadrant species who visited Earth some 45,000 years ago and gave a genetic gift to the ancestors of Chakotay's people, who remembered them as the Sky Spirits.
The Sky Spirits are an advanced humanoid species from the Delta Quadrant who appear in the Voyager episode Tattoo. Tens of thousands of years ago they came upon a small group of nomadic hunters on Earth, and were so impressed by their respect for the land that they gave them a genetic bond, encouraging their curiosity and their migration into the Americas.
In 2372 an away team finds a symbol on a moon which Chakotay recognises from a journey he made as a boy with his father, Kolopak, to meet the Rubber Tree People of Central America. The trail leads to the aliens' world, where storms drive Voyager away.
Chakotay meets them alone. They had believed their adopted people wiped out by later conquerors, and he assures them that the descendants survive. The Sky Spirits bear the same mark on the forehead that Chakotay wears as a tattoo.