The Etherians were a peaceful, intelligent, flying species who were encountered by the USS Voyager in the Forge's 'graveyard' field in 2376. Teams from Voyager boarded an Etherian ship while it was trapped in the graveyard around the Forge to find out more about learn more about their surroundings.
The Voyager Hazard team began exploring the ship but gradually began encountering increasing resistance from the Etherian crew. Eventually, each member was captured, apart from Alexander Munro/Alexandria Munro and Les Foster. It was then discovered that the Hazard team had boarded an Etherian sleeper ship which was on a journey to a new homeworld when the Vohrsoth probe transported them to the graveyard. After the establishment of peaceful relations, the Etherians and the Voyager crew became allies.
In the final battle between the Vohrsoth leader and Ensign Munro, the Etherians assisted the battle by destroying The Seed. It is believed that the Etherian sleeper ship returned on its journey to its new homeworld.
Not much is known about Etherian technology except that it appears to be bio-mechanical. The full capabilities of their technology is not known, but individual Etherians were capable of firing electrical bolts of energy which may have been either natural or mechanical. They also possessed internal 'spawn' transporters which transported Etherians into stasis when they were injured. Mechanical drones also protected the ship by regenerating damaged systems with abilities that may have been a form of replicator technology.