The Thirteenth Sword is the ship of Captain Dreadlove. She is so large that no port in the world is built capable of servicing her. Her sails are little more then frayed black rags displaying a vast skull and crossbones. She's seemingly driven forward by the baleful fog that follows (or perhaps imprisons) her wherever she goes.
The ship's prow depicts a huge shark's face, the mouth of which opens when the Sword moves in to ram another ship. Her hull appears to be a mishmash of exotic and precious metals interlaced with rotten black-green wood, and is incredibly resistant against bombardment of almost any kind.
The ship's harpoons apparently reveal themselves to be large venomous centipedes when they miss or efforts are made to remove them. There are rumors, wild and unsubstantiated, of a variety of other supernatural qualities, including that the ship can travel on land, parting earth and stone as easily as waves.
She is crewed by nightmarish patchwork people, apparently sewn together and animated by the Captain's blood from pieces of his victims that, for whatever reason, he took a liking to. Some start off as live prisoners, captured as loot. Over time they are 'gifted' with parts from other victims that are stronger or more beautiful then their own.