The Invidian Battalion were a Cardassian military unit within the Cardassian Guard. During the Occupation of Bajor, this battalion were charged with "managing" the southern provinces of Bajor. The Bajorans themselves noted that they were a death squad that was dispatched by the Cardassian Union.
Two Cardassian bodies were discovered on Deep Space 9 in 2375, Elim Garak noted that their clothing identified them as members of the Invidian Battalion. (DS9 - Millennium novel: The Fall of Terok Nor)