The Dar'hen Pirates operated in Wild Space and were known to attack New Republic vessels as they headed into the Unknown Regions. When they almost captured Nemhain and destroyed most of Banshee Squadron, Rogue Squadron took action.
They ambushed a Dar'hen freighter convoy and captured its lead ship, using it to locate the Dar'hen headquarters - a hollowed out asteroid defended by hidden laser batteries. It was completely destroyed, and the Dar'hen Pirates haven't bothered anyone since.
Dar'hen's forces relied heavily on starfighters. They had invested in a variety of fighters, such as Cloakshapes and T-Wings. Their capital ships were limited, meaning they could do little to defend themselves against Rogue Squadron's warships.