The Cardassian First Order was a military division of the Cardassian Central Command. The Third Battalion of the First Order was a Cardassian unit known for their fanaticism. Their motto was "Death to all."
Three members of the Third Battalion were left on Cardassian space station Empok Nor in stasis when it was abandoned. They were test subjects of a failed psychotropic drug designed to heighten their xenophobia. Only two of the three were released when the Starfleet personnel entered the station, the third was dead due to a broken stasis chamber. (DS9: "Empok Nor")
During the Dominion War detachments from this order, according to Damar's speech at the start of the Cardassian Rebellion, attacked the Dominion outposts and cloning facility on Rondac III. (DS9: "The Changing Face of Evil")