Klingon-Cardassian Alliance
In the Mirror Universe, the Klingon-Cardassian Alliance was the historic union of the Klingons and the Cardassians, two former enemies, in the face of aggression from the Terran Empire. Following a series of reforms by Spock, the leader of the Empire, the Alliance conquered the Empire, enslaved Terrans and Vulcans, and became the dominant power in the Alpha Quadrant throughout most of the 24th century.
A Regent led the Alliance, delegating authority to various Intendants who administered individual sectors of Alliance territory.
It is unclear whether the Alliance had a central location of government, on either Qo'noS, Cardassia or elsewhere.
Bajor became a sovereign planet in the Alliance by the late 24th century, after the Alliance liberated Bajor from the Terran Empire.
In the latter half of the 24th century, a Terran rebellion against the Alliance was created due to interference from individuals from the primary universe. (DS9: "Crossover")
By 2408, the KCA had been overthrown as a complete controlling power of the territories of the Prior Terran Empire. The Imperial Union of Planets was founded by Rodrigo Doenitz and was at war with the KCA to regain the territories that had once belonged to the Terran Empire. The KCA, however was far from beaten.
In Mid- 2408 The planet Sunali II had defected from the IUP and joined the KCA. The ISS Rosenante destroyed Sunali II and the assembled KCA taskforce using an Omega Device. This singular act destroyed dozens of KCA ships and made the Sunali system a hazard to Warp Navigation.