Destroyers are a midsize warship, but are larger than and outrank frigates. They are the largest kind of warship that is able to carry torpedo launchers. They are extremely versatile in battle, sometimes being used as escorts for cruisers and battlecruisers in larger fleets while other times serving as the flagship for smaller fleets. Their torpedoes make them a formidable threat to larger warships, even battlecruisers and battleships, while their speed and maneuverability make them a formidable threat to smaller warships, such as frigates and especially corvettes. The only reason these ships aren't more widely used than frigates is because of their manufacturing cost. Destroyers are not available commercially, and only the few most feared pirates have managed to bring a destroyer into their fleets.