Yaer'aed Empire

The Yaer'aed Empire, also known as the Yer'ed Empire or Yered Empire, (Eber-iub Yaer'aed-xhie, "realm of the children of the goddess Xhi") was a large ancient interstellar empire and one of the first known galactic civilizations, second oldest only to the Khrezhes civilization. It was founded and ruled by the Yaer'aed species, who in modern times continue to be the subject of much debate and intrigue by scholars and xenoarchaeologists due to what little information survived about them to the present day. The Empire was the largest state of its time, spreading to nearly one-third of Andromeda at its peak. Its founding species' influence remains to this day in modern Imperial culture.

Origin
How exactly the realm was founded remains a mystery. It is unknown when the Yaer'aed first began starfaring but the best estimate is somewhere around 8000 to 6000 AE. Most Yaer'aed structures have fallen into severe decay or have disappeared altogether, which gives curious xenoarchaeologists little to go by with piecing together the empire's history. Only pieces and fragments of hyperdrives and ships have been found, making their methods of space travel also a mystery.

Rise to power
The Yaer'aed began to spread from their homeworld of Viwei around 8000 AE, colonizing the surrounding systems over the surrounding decades. Their empire saw a slow growth over the next couple millennia, reaching its peak around 4200 AE. It is during this time that many surviving Yaer'aed structures date to. It is likely that the Yaer'aed did not encounter any other species near its intelligence, as galactic life was still developing.

Decline
During this time, the Empire began to become fragile and its size slowly shrunk, possibly even as small as five planets around its homeworld of Viwei during its very end.

Collapse
It is unknown how exactly the Yaer'aed Empire fell, and even when. The likely date is around 2000 AE, and probably due to political instability because of the Empire's sheer size. The Yaer'aed mysteriously disappeared soon after, leaving behind their cities and temples, and the cause of this is not known. Some have suggested that the Yaer'aed travelled to the neighboring Triangulum Galaxy, where they began a new life there, and later evolved into the Nekkyri species due to the anatomical similarities the Nekkyri supposedly have with them. Others refute this hypothesis and state that they simply went extinct for a reason not yet known.

Legacy
The Yaer'aed left behind a legacy of mystery that many people have tried and failed to piece together. The few snapshots of their history that they left behind offer only tiny explanations of what their empire or history was like.

Elements of modern Imperial culture and language owe themselves to the Yaer’aed. Due to their influence on Thodron, a planet once on the edge of their empire’s borders, the Thodronese language, in the modern day a galactic lingua franca, owes many of its vocabulary to the language of their former overlords. Thodroni themselves also benefitted from the Yaer’aed with the cities and technology they left behind, which further sped up their advancement as a species.