The Achilles was a Sword Class Frigate that took part in the evacuation of Belatis during the 12th Black Crusade. While the evacuation was under way, the Achilles and its squadron were, together with the Dragonrock ,on patrol in the exterior area of the system for detecting hostile units.
When the renegades on the surface managed to seize control of the defence-laser stations and to fire at the fleet in orbit, one antagonistic fleet under the guidance of the Charybdis broke out of one of the gas giants. The Pegasus - a sister ship of the Achilles - noticed the ships of chaos at first and thwarted them, giving the evacuation fleets precious time. It was lacerated by a salvo of torpedoes of the opposing escort from ships of the Malediction Class. Only shortly after, the Achilles succumbed to a salvo of plasma from the Charybdis, but heavily damaged an opposing escort-ship before.