The Shyedarian Revolution had been raging for over half a century, with no end in sight. Then, roughly six years ago, a new factor appeared: the Vraath, who had been stealthily observing the situation in the Zulu Sector, launched a full-scale invasion simultaneously against both the Shyedarian Empire and the Rebel systems.
Rebel leaders felt that the only way for either side to survive the Vraath invasion was for both sides to join forces to try to repel it. The Shyedarian Emperor, on the other hand, favored throwing all of the Empire's resources into a quick conquest of the Rebellion, which would then allow them to use the Rebel's captured resources to try to fight back the Vraath. However, the Emperor misjudged his support base, and was surprised when a significant number of Shyedarian Great Houses, led by Prince Vrilnashter, threatened to break away from the Empire -- ensuring its destruction -- if the Emperor did not abandon his ambition and agree to an alliance with the Rebellion. The result was the Treaty of Kyuusei, named after the last world the Shyedarian Empire and Rebellion fought over when the Vraath invasion struck. This treaty, followed by the Kydheril Accord, formed the foundation for the Commonwealth of Independent Systems.