The militaristic interstellar state of the Cardassians, notorious for its occupation of Bajor and its later alliance with the Dominion.
The Cardassian Union is the state of the Cardassians, governed from Cardassia Prime. For much of the 24th century it is dominated by the military through Central Command, with the Obsidian Order keeping the population under surveillance, while the civilian Detapa Council holds little real power.
The Union occupied Bajor from 2328 to 2369 and fought a long, bitter war with the Federation that ended in a treaty and the creation of the Demilitarized Zone. In 2372 a civilian government took control, prompting the Klingon invasion that opens the fourth season of Deep Space Nine.
In 2373 Gul Dukat brought Cardassia into the Dominion, but the alliance soon became an occupation. Legate Damar led a rebellion against the Dominion, which retaliated in 2375 by killing hundreds of millions of Cardassians before the war ended.