Nagga

Nagga was the sea dragon of the ironborn legends, slain in the Age of Heroes by the Grey King, who is said to have worn a tall pale crown made from her teeth. When she was dead the Drowned God turned her bones to stone, and from her ribs the king raised his hall on Old Wyk and warmed it with her living fire; when he walked into the sea at the end of his thousand-year reign the Storm God snuffed the fire out and the waves stole his throne, and only the bones remained. Nagga's Ribs still stand on the hill above the shore of Old Wyk, grey stone pillars where the ironborn gather for their kingsmoots, and the priests of the Drowned God count her among the god's oldest gifts.