Romulus is a Cannon Fist user and the vice captain of the Mantle Pirates. His NPC counterpart is found at Savaria, aboard a damaged version of the Rumbling Caldera, stationed by the shore. Here, you are able to talk to Romulus and learn the fighting style Cannon Fist. Romulus also has a backstory, The Plight of Romulus, found in a book in-game.