The Koranak is a Keldon-class Cardassian warship that was taken by the Obsidian Order and altered with enhancements to its speed and weapons capabilities.
It is also equipped with a Romulan cloaking device provided by the Tal Shiar. It was part of a fleet that protected the Orias System and later joined in a failed attack by the joint forces of the Obsidian Order and the Tal Shiar on the Founders' Homeworld.
The attack was ambushed by the Jem'Hadar and the fleet was completely destroyed.