Born in Flea Bottom to a life of hardship, Davos took to the sea aboard the Cobblecat under the Tyroshi pirate Roro Uhoris, and afterward bought a black-sailed ship of his own and made himself one of the most notorious smugglers in the Seven Kingdoms. Near a year into the siege of Storm's End, with the garrison eating rats and boot leather, he ran the Redwyne blockade of Shipbreaker Bay with a hold full of onions and salted fish, and bought Stannis Baratheon's men the weeks they needed until Lord Eddard Stark broke the siege. Stannis knighted him for it and granted him lands on Cape Wrath, and then, for the years of smuggling that came before, took the first joint from every finger of his left hand. Davos judged the sentence just and asked only that the king swing the blade himself. He carries the bones in a pouch at his throat and counts them lucky, for they bought a future for his wife Marya and their seven sons.
When Stannis claimed the Iron Throne after Robert's death, Davos captained the Black Betha in his fleet and served as his envoy, recruiting the Lysene sellsail Salladhor Saan and riding the stormlands to sound out Swann, Penrose, and Tarth, none of whom would come. He was the only man at Dragonstone to make room on the bench for old Maester Cressen the night the maester poisoned himself trying to kill Melisandre, and he never afterward trusted the red priestess. At Storm's End he rowed her beneath the walls in the dark and watched her give birth to the shadow that killed Ser Cortnay Penrose. He warned Ser Imry Florent to scout the Blackwater before entering it, and was ignored; the chain went up, the wildfire took the fleet, and Dale, Allard, Matthos, and Maric all died in the river while their father was thrown into the bay and washed up on the spears of the merling king.
Rescued by one of Salladhor's ships, Davos returned to Dragonstone meaning to murder Melisandre and was arrested with the dirk still on him, but his honest counsel against Ser Axell Florent's plan to put Claw Isle to the sword won him his life and more — Stannis named him Lord of the Rainwood, Admiral of the Narrow Sea, and Hand of the King in Alester Florent's place. He learned his letters from Maester Pylos, smuggled Edric Storm off the island rather than see the boy burned for a prophecy, and, with the king's sword at his neck for it, read aloud Maester Aemon's plea from the Wall and so turned Stannis north. Sent afterward as envoy to White Harbor, he was condemned in open court by Lord Wyman Manderly and reported beheaded, his head and hands mounted above the city gates; in truth a look-alike died in his place while Wyman kept him hidden in the Wolf's Den, and by the close of A Dance with Dragons the Onion Knight has been sent to Skagos to bring back Rickon Stark.