The loose underground of teachers, students and officials who worked against the rule of the Central Command and the Obsidian Order, and whose aims were realised when civilians took power in 2372.
The Cardassian dissident movement is introduced in the Deep Space Nine episode Profit and Loss, when a damaged ship brings Professor Natima Lang and her students Hogue and Rekelen to the station. Lang, once Quark's lover, teaches that the military must give up power, and the Central Command wants all three dead. Garak lets them escape.
Second Skin shows the movement reaching into the leadership itself. Legate Tekeny Ghemor of the Central Command is a secret sympathiser, and the Obsidian Order tries to expose him by convincing Kira that she is his lost daughter. Ghemor flees into exile and reappears in Ties of Blood and Water.
After the Obsidian Order is destroyed, the dissidents overthrow the Central Command and hand authority to the civilian Detapa Council, as reported in The Way of the Warrior. The Klingon invasion and Dukat's pact with the Dominion soon undo their work.