The Ethreni are non-corporeal lifeforms whose homeworld, Ethra, was denuded of all corporeal life in the distant past by increased stellar activity and radiation from their system’s binary stars. For millennia, The Ethreni were stranded on their dead homeworld until human explorers arrived to gather materials in the early 3300’s. The Ethreni found communicating with the humans impossible, since The Ethreni possess no technology and human instrumentation simply could not detect creatures of pure thought and will.

However, with their powerful mental abilities, The Ethreni swiftly discovered they could inhabit the minds of humans when they entered their curious daily sleep cycle – forcing the humans to remain in an extended sleep pattern, and allowing The Ethreni to control the corporeal human body. Further, human inhabitation also enabled The Ethreni to gain the full knowledge, skills and experiences possessed by the human explorers, and to experience the corporeal universe as humans do.

Initially, human inhabitation was simply a means for The Ethreni to escape their dead homeworld, but very quickly The Ethreni came to experience a certain delight from exploring the universe in corporeal human form. Some Ethreni enjoy one human inhabitant above all, while others seem to favor hopping from one inhabitant to another, resulting in the unsettling certitude that an Ethreni’s physical appearance can be that of any human. Due to their non-malicious nature and the sheer joy that corporeal human inhabitation provides, The Ethreni never wittingly put their inhabitant (or any potential inhabitants) in danger.

In the few years since first contact, The Ethreni have expanded throughout humanity’s entire reach, and have found that they can inhabit most living creatures and plants (which they dislike), although they prefer sentient species – like humans. Preferring human explorers to all others, The Ethreni are patiently seeking a new homeworld for themselves; one that is long-lived, filled with all manner of corporeal living creatures, and one which will provide the necessary environment to sustain their human inhabitants – most likely an earth-like world possessed of very specific properties and parameters.