Davos Seaworth
The Onion Knight: a former smuggler raised to knighthood for feeding a starving Storm's End, now the most honest man in Stannis Baratheon's service — and the least comfortable at court. He shortened his own fingers to pay for his crimes.
A soul born at Flea Bottom, King's Landing, sworn to House Seaworth.
The fuller tale
Season Two
Stannis's man in every sense but the title, a smuggler knighted for running onions through a siege, missing the fingertips of one hand for the crime of smuggling before that. He distrusts Melisandre and says so to Stannis's face, which no one else dares, and watches her deliver Renly's death alone in a sea cave. At Blackwater he captains the flagship into the bay, sees the green wildfire swallow the fleet around him, and loses his son Matthos in the water. Stannis abandons the siege before Davos is found; he survives, barely, on driftwood and salt water.
Season Three
Fished half-drowned from the bay and thrown into Stannis's dungeon anyway: he cannot out-argue a red priestess for a king's ear from outside the room, so he tries to kill her instead, and fails. He learns his letters there, coached through the bars by Princess Shireen, an old smuggler doing his alphabet like a child. When Gendry is brought to Dragonstone to be bled with leeches for a blood magic Davos wants no part of, he rows the boy out to open water and sets him free, and is thrown back in his cell for it — until a raven from the Wall changes what Stannis needs him for.
Season Four
Made Hand of the King over Melisandre's objections, and spends the season translating Stannis's stubborn honor into the only currency that actually moves it: coin and timing. He talks his king into borrowing from the Iron Bank rather than losing his claim by default, and talks him into marching for the Wall when every other lord would have stayed south chasing the throne instead. At Castle Black he watches Stannis's cavalry break the wildling host in the nick of time, the reward for having read a letter nobody else in the castle took seriously.
Season Five
Sent ahead to Castle Black to arrange provisions for Stannis's march on Winterfell, and it turns out to be lucky timing of the worst kind — he is behind the Wall's gates, not in the camp, when grief and Melisandre and a stalled march talk Stannis into burning his own daughter for wind and favor. He returns to find Shireen already gone and a war he no longer believes in, and quietly buries what was left of his loyalty to Stannis somewhere in that snow.
Season Six
Finds Shireen's small burned bones outside the ruin of Stannis's camp and carries that discovery like a blade for the rest of the season. At Castle Black he backs Jon's return from the dead with blunt practicality — dead men don't get to stay retired when the living still need them — and rides the North's back roads drumming up swords for the Battle of the Bastards. Afterward, in front of the victorious lords, he calls Melisandre to account for Shireen and has her banished, on pain of death, from ever setting foot in the North again.
Season Seven
Jon's steadiest counselor now, the one who keeps saying the plain thing everyone else is too proud to say: go to Dragonstone, ask the dragon queen for help, dragonglass is dragonglass wherever you find it. He sails south with Jon, needles Missandei and Tyrion in the same breath he flatters them, and talks his way past a locked gate to get an audience with Daenerys at all. Beyond the Wall on the wight hunt he stays behind with the boats, too old for that particular argument, and is still there when the survivors come stumbling back across the ice.
Season Eight
Master of Ships in every way but name, running supply and strategy for a war he privately expects to lose. He argues for patience against Sansa's hoarding and loses that argument gracefully, mans the defenses at Winterfell through the long night, and lives to see the dawn he doubted would come. In King's Landing afterward he watches the war end in ash rather than victory, and takes a seat on the small council that rebuilds the Seven Kingdoms — Hand's work in every sense but the title, again, this time for a king he actually chose.
How it ends for them
The chronicle records no death for this soul — they are living when the tale leaves them, or their ending is a page the maesters have yet to turn.
Their chapters, book by book
A Clash of Kings 3 chapters of their own
A Storm of Swords 6 chapters of their own
A Dance with Dragons 4 chapters of their own
Where the page and the screen part
Book Davos is a point-of-view character and the books' quiet moral instrument — his chapters carry Dragonstone's politics, the burning of the godly, and the case against Melisandre from inside. His family is bigger (seven sons; the show keeps one), his letters come from Maester Pylos rather than Shireen (the show's swap is one of its best inventions), and his later road diverges entirely: White Harbor's fake execution — his 'head' on a spike belongs to a criminal — and the secret mission to Skagos for Rickon Stark are still in motion in the books, while the show quietly handed the Rickon thread to other characters and kept Davos at the Wall. His survival past Stannis's fall is show-only so far; in the books his king still lives and Davos still serves him, at a distance of half a kingdom.
Their journey
Where the two tellings send them to the same place the road runs whole; where they part, the screen keeps the left and the books the right.