Cosa

The Cosa were a race native to the Silent Sector in the Outer Core of the galaxy that reached the fifth tier of the civilisation scale. They were one of the longest and most stable cultures in the region but were defeated and made extinct by a war with the Encased, a technologically inferior but extremely aggressive race also native to the sector.

History
The Cosa civilisation developed from the unification of their home-world following a series of political revolutions leading to a single party government claiming sovereignty over the entire system.

First contact was established by Observer explorers surveying the system for colonisation and the government when the Cosa had reached tier IV of the scale of civilisations. A generation later the first Cosa left their solar system and began settling other worlds.

Early efforts by the Cosa were to establish lines of communication between their colony worlds and the home-world to allow for near direct governance as possible. This was threatened by the advancement of a nearby race, the Vida, who claimed certain systems in between certain colonies and the home-world which could have led to a lowering of the influence the central party had over outer worlds. After a series of diplomatic incidents the two races went to war.

During the war the central party of the Cosa began to lose control of some of the distant colonies, in response they ordered their astral naval forces to step up the war leading to the genocide of the Vida. This had the desired effect, the war was won and the rebellious colonies soon stepped back into line once the warships were diverted to their systems.

Following the war the central party's attempts at absolute control over their colonies began to lax as pressure from neighbouring races in the sector that saw the destruction of the Vida as being extreme. The Cosa lost a great deal of credibility in the sector and slipped out of local affairs for a few centuries, returning later after a number of generations to weigh in their interests in expansion.

Following the sudden an devastating attacked by the Encased, wherein every major military instillation was attacked simultaneously the Cosa were once again brought into a war. Believing their technological advantage to be enough to destroy the relative upstarts in the galaxy their fleets were sent into Encased space. While initially successful, the Encased appeared to adapt quickly and managed to capture a number of Cosa vessels. After losing contact with their main fleet, the Cosa home-world was bombarded by a surprise attack by a previously unknown Encased fleet. The loss of the central party's authority through the outer colonies into turmoil and the Encased were able overcome their disorganised defences. The Cosa were wiped out almost totally by the Encased with the few survivors finding refuge in neighbouring civilisations.