At first, Davos was just a punk in the flea nest in King's Landing. Later, although he was able to get married, marry and have children, his livelihood was as a smuggler at sea and engaged in illegal activities. Until one day, a war broke out for the purpose of overthrowing the cruel monarch "mad king" of the old dynasty, which swept the whole continent. It was in this war that Davos's fate changed.
In this war, the "mad king" sent troops to surround and block the former residence of the rebel Baratheon family. Stannis is in charge of guarding the city Baratheon persisted in resisting and refused to surrender, so that the defenders of the whole city had to eat rats for a living. Just when Fengxi Castle was about to run out of ammunition and food, Davos seized the opportunity and broke through the sea blockade by relying on his superb driving skills of smuggling ships all the year round, and sent a batch of smuggled onions as food to the soldiers guarding Fengxi Castle. It was this batch of onions that enabled Fengxibao to successfully hold the day of victory in the Anti-Japanese War.
Stannis was moved by this timely help, and he knighted Davos-then he changed his face and personally cut off four fingers of Davos's left hand with his sword as a punishment for being a "smuggler". Although Stannis's other nobles were very grateful to Davos, considering that he became a knight by smuggling onions, he actually looked down on him in his heart and even cynically called him the "onion knight".