Cardassians, Mirror Universe

Star Trek: Deep Space Nine
Episode: DS9 443 - Crossover

Planet: Mirror Cardassia. Cardassians would still seem to harbor the same attention to detail as ever in the Mirror Universe, where they likewise seem as efficient as always, whether in killing or administrating. They have entered into an Alliance with the Klingons there after defeating the Terran Empire — mostly filling security and defense positions. Uniforms, demeanor, equipment and ships all appear to be exactly the same.