Risa of the mirror universe was not unlike its counterpart in the main Federation universe. It was a pleasure planet which catered to the desires of its many visitors. Citizens of the Klingon-Cardassian Alliance could enjoy exotic liqueurs, swim in crystal-clear oceans or partake in gambling at the planet's many casinos. However, visitors to this Risa could also avail themselves of far more dark pursuits such as an encounter with the planet's many harems whose members were trained as virtual sex-slaves or engage in odd sporting events such as murder-for-thrills. (Decipher RPG module: Through a Glass, Darkly)
Although located well within the borders of the Alliance, Risa was able to maintain its independence through a combination of political manipulation, bribery and treachery.
The leaders of Risa were well familiar with the Cardassian system of vesala, or the art of influence, and used it to prevent the installation of an intendant. Those few officials who could not be dissuaded saw their end through hired Flaxian assassins. (Decipher RPG module: Through a Glass, Darkly)
In 2377, the freelance archaeologist Luc Picard and his companion Deanna Troi unearthed the Tox Uthat artifact on Risa after spending five years looking for it. The two Vorgons Ajur and Boratus attempted to force it from Picard with the assistance of Gul Edoka but were foiled by the Memory Omega operatives K'Ehleyr and Reginald Barclay. When K'Ehleyr destroyed the artifact, the Vorgons left and Picard and Troi were informed about Memory Omega's existence. (ST - Mirror Universe novel: Rise Like Lions)