Seskans

Seskans are one of few confirmed alien species that managed to created an interstellar civilization. One, however, that existed rather briefly and remained rather hard to understand by modern humans. It is also one of the few extinct sapient Xeno Species whose exact look is more or less known and, in fact, mostly humanoid.
Their downfall was certain long before they left their homeworld. Seskans were driven by a strong instinct for expansion and strength. They were an extremely militant society, that suffered from an almost constant internal strife. The development of their 'empire' happened mostly because of the need to find places where the defeated could run to and avoid getting repeatedly stabbed in the eye. It was less of an expansion and more of escape.
It is unknown how they actually managed to survive when bound to the same planet. Probably by only narrowly outpacing their deaths with reproduction. Their empire was located in the Northern American Oversector, however it was little more than a core of systems surrounding their homeworld. Seskan expansion reached most of southern Milky Way, however it was extremely 'thin', with a single Seskan sometimes occupying a whole star system.
After destruction of their central systems by an unknown disaster (suspected to be a war against Screamers, most of the outlying settlements simply died out, without their cradle that kept producing new exiles.

Basic Information

Anatomy

Humanoids of roughly human size (two meters when adult, up to two and a half meters). They seem to have been created by an evolutionary route slightly similar to Earth's fungi, however one that required spores of two different 'genders' to mix. Covered in a slightly fur-like matter that was in fact used as their prime senses (touch, smell, taste and something akin to rudimentary echolocation). It was also used to eat, by dissolving and absorbing organic matter.
They also seemed to possess some sort of hereditary memory, with newborn seskans born with the general outline of knowledge of their predecessors.

Genetics and Reproduction

Spores of two genders, mixing and gestalting a new seskan that seemed to 'grow' from thin air. The biggest problem was that this proccess seemed to directly rely on the overall number of spore-producing seskans around, since only small number of spores mixing actually ended in new seskan being born. The more of them in the planet atmosphere, the more of new seskan spawned. This meant that only their coreworlds had significant number of them born each year - the bases and outposts around them were esentially barren, with a single seskan being birth once in many, many years and only when a few of them already lived there.
The exiles essentially couldn't give birth, with only the central systems (with their significant and centralized population) being able to do that. Exiles often lived alone on a planet, and when there were few of them, in most cases they were mutually hostile (which especially on a barren planets made procreation impossible).

Civilization and Culture

Average Technological Level

Quite advanced robotics and general technology, but what the seskans truly excelled in was the level of automation. A single seskan could easily command a battleship-size warship on his own, by using extremely efficient programming and vast number of automatas.
Due to their hereditary memory, each seskan was a true jack of all trades that could construct a well defended base together with a small fleet of warships to protect it... on his own, if given enough time. And they didn't even have to eat or drink in traditional sense of the word, since they seemed to be able to filter both from air (either naturally existing or artificial, within the constricts of their base). Both seskan themselves an their installations and units seemed to literally spring up from the ground out of nowhere.

Notable Xenotechs
Seskan MAW

History

Seskans evolved on a Terran-like planet somewhere in the Northern American Oversector, probably between Sectors 11 and 40 of the Human Space. Several of their coreworlds were located, most of them creating clusters of 5-6 systems, and spread throughout the whole area. Finding out which of it was their homeworld is impossible, due to them being completely destroyed.
They spread throughout great area due to their instincts that literally forced them to expand, however overwhelming majority of such expansion was done by a single seskans surrounded by small armies of robotic servants, fleeing the relentless infighting that plagued their coreworlds. That made all of that colonies temporary, as sooner or later (in most cases later, since they could live up to 200 years) they died out.
They seemed to have a brief contact with Aurums whom they fought but seemed to be soundly defeated, but for some reason avoided the area of Orion Spur where Earth was located. The reason for this is unknown and an object of hot debate. Majority of their Exiles settled in the rest of the Sagittarius Arm, but their remains were encountered also in Scutum-Centaurus, and in Perseus Arm. There are also some supposedly found in the insectoid-controlled part of Norma Arm.
Because of that and generally low number of their ships found in Hyperspace, it is commonly believed that most of their expansion was done by using a variant of Alcubierre Drive, that was later on completely abandoned, which split their space according to hyperlanes. The cause of that was unknown, but it contributed to the eventual fall of seskans.
Their coreworlds are believed to be destroyed by an unknown enemy around 1st-2nd century AD. The most possible suspect are screamers, but the wreckage fits that theory only partially. What's more, if the screamers did expand, who pushed them back into the Triangle? Regardless of the identity, the mysterious enemy was quite thorough. Seskan coreworlds were completely destroyed, with most of their atmosphere scorched completely to make sure their spores are destroyed. The seskan outside of them (most of them not even aware of the devastation due to being cut off from the coreworlds by abandonment of Alcubierre Drive) simply died out in the next two to five centuries.

EXTINCT