Unnamed Species: HIE121CZE
Xenosophonts which vanished 31 million years ago.
Details are still unclear about HIE121CZE, mainly because all ruins, ships, and even bodies of this species were systematically destroyed by three other starfaring civilizations. Our information is primarily from fragmentary accounts, preserved by the Muuh and independently by the Silent Ones of why the ruins were being destroyed, and therefore may contain an obvious bias caused by war propaganda. Such vague stories would normally be disregarded, except for the fact that the accounts given by both species are remarkably consistent.
About 31 million years ago species HIE121CZE was apparently a peaceful, slowly-advancing starfaring race setting up colonies on carbon planets. Then there are reports of a sudden change in their society, after the colonization of an unidentified planet which had been occupied by an extinct race. Species HIE121CZE rapidly became highly organized and expansionistic, and apparently attempted to merge organic and technological elements in their bodies. The purpose is unclear; the received accounts mainly emphasize the threat level and the need for extreme measures to exterminate the threat. This resulted in a massive war and the widespread use of advanced weapons of mass destruction.
The accounts mention that the last survivors of HIE121CZE scattered in suicidal attempts to preserve some of their machines--often sacrificing organic lives to hide the locations of random, seemingly useless bits of technology which had been stashed on different worlds all across the galactic arm. Apparently this effort was futile, for no known relics of HIE121CZE have ever been found by human expeditions. It is thought that the homeworld for this species no longer exists in recognizable form due to the war.