The reptilian Cardassians are raised to value service to the state above all other goals. Cardassians are bold, and ruthless. For ages the Cardassian Empire has been ruled by a union of the two autonomous branches of government: the military and the Obsidian order. So public service usually took the form of war or spying. Although this government was annihilated by the war with the Dominion, this tradition makes them excellent security and tactical officers.

Cardassians occupied Bajor for over 50 years, a brutal regime that enslaved the population and slaughtered resisters.

I have no idea what Cardassians are doing on this playable character list. They’ve always been villains. But the story line for Star Trek Online takes place 20 years after Nemessis, and we don’t have any information on Cardassian politics following the war with the Dominion.