High Quality Content by WIKIPEDIA articles! The Cardassians are an extraterrestrial species in the Star Trek science fiction franchise. First introduced in the 1991 Star Trek: The Next Generation episode "The Wounded", the species originating on the fictional Alpha Quadrant planet Cardassia Prime. Cardassians were the dominant species in an interplanetary empire known as the Cardassian Union, ruling over other species, including the Bajorans, during the 24th century. The Cardassians later played a key role in the storyline of the series Star Trek: Deep Space Nine as allies of the Dominion in the Dominion War. Several Cardassian characters, including Elim Garak and Gul Dukat, are prominently featured.