Alliser Thorne
Master-at-arms at Castle Black, a bitter, hard-handed old knight who fought for the losing side in the rebellion and has hated soft southron boys ever since.
A soul born at The Crownlands, sworn to The Night's Watch.
The fuller tale
Season One
Master-at-arms at Castle Black and about as warm a welcome as the Wall has to offer: a knight with real battlefield credit behind him, reduced now to beating discipline into thieves and poachers, and he does not let any of them forget what he thinks of the job. He rides Jon Snow hardest of all the new recruits, resents the boy's swordsmanship and his highborn manners in equal measure, and loses the yard fight badly enough to make it personal. When Mormont needs proof of what came over the Wall carried south to a court that will not want to hear it, he sends Thorne with the wight's severed hand — a punishment dressed up as a mission, and Thorne knows it.
Season Three
He comes back from King's Landing to find the Watch he left in worse shape than the one that sent him away, and Castle Black very obviously being run in his absence by men he does not respect. Jon Snow returns from beyond the Wall having lived and fought and slept among wildlings, and Thorne says out loud what plenty of others are only thinking: that a man does not come back from that unmarked, and the Watch would be foolish to just take his word for which side he is actually on. He pushes for Jon to be tried as a deserter and spy rather than welcomed home, and loses that argument, which does nothing to change his mind.
Season Four
With Mormont dead and no Lord Commander elected, Thorne is one of the men effectively running Castle Black, and he runs it the way he has always wanted to — hard, humorless, and suspicious of Jon Snow's judgment on principle. When Mance Rayder's army finally reaches the Wall he fights the siege seriously, holding the gate and the top of the ice with men he has spent years training, whatever else is said about him. Stannis Baratheon's cavalry breaks the wildling army at the last possible moment, and Thorne survives the battle that killed better-liked men than him, which he seems to take as vindication rather than luck.
Season Five
He stands against Jon Snow for Lord Commander and loses a close vote, and takes the defeat the way he takes everything — as one more piece of evidence that the Watch has lost its sense. Jon's decisions once in command only confirm it as far as Thorne is concerned: bringing wildlings south of the Wall to live as neighbors instead of enemies, arming the same people who spent the season trying to kill them all at Hardhome. Thorne says nothing shows the rot more clearly, and he is not alone in saying it. He, Bowen Marsh, and a circle of officers who have run out of patience corner Jon in the courtyard at Castle Black and each put a knife in him, telling him it is for the Watch as he dies.
Season Six
He holds Castle Black in the days after the mutiny, tells the men who still trust him that it was necessary and that the Watch is better for it, and does not flinch when Sansa Stark's letters and Tormund's wildlings start pressing at the gates from outside. When Jon Snow comes back from the dead and the castle will not fight for a ghost, Thorne surrenders it without much of a struggle, unwilling to burn Castle Black down over a battle he already knows he has lost. He is hanged for the mutiny in the yard alongside the other ringleaders and the boy who fired the last arrow, and goes to it without protesting his innocence or begging — the one thing about him nobody watching can find fault with.
How it ends for them
On the screen. Hanged at Castle Black (S6·E3)
First Ranger, mutineer, and Jon Snow's oldest enemy at the Wall — he led the knives 'for the Watch' and hanged for it when Jon rose again. He went to the rope unbowed: 'I fought, I lost. Now I rest.'
In the show he finishes what he started. Leading the mutineers, he puts a knife in Jon Snow’s heart beside the sign that reads traitor, holds Castle Black against Davos and the loyalists, and loses when the free folk arrive with a giant. When Jon returns from the dead, his first and last act as Lord Commander is the sentence: Thorne hangs beside Olly and the other mutineers, and goes to the rope with his spine straight — he fought, he lost, now he rests, and he’d do it all again. Jon cuts the ropes down himself and leaves the Watch with the bodies.
In the published books he is alive, so far as anyone knows — dispatched beyond the Wall on a ranging by the Lord Commander he loathed, and not yet returned when the knives came out at Castle Black. Whether Jon meant the mission as employment or exile is left for the reader to weigh; Thorne himself suspected the latter, loudly.
Their chapters, book by book
A Storm of Swords 1 chapter that name them
Where the page and the screen part
Book-Thorne is a pettier creature with a smaller part. He duels Jon with insults rather than conspiracies, and his great humiliation is an embassy: sent to King’s Landing with a wight’s severed hand to prove the dead are rising, he waits so long for an audience that the hand rots to bone, and Tyrion laughs the Watch’s evidence out of court — a scene that quietly explains why the realm never came to help. By the time of Jon’s command, the books have shipped him off to Eastwatch and then out on a ranging from which he has not returned; he has no part in the mutiny, whose knives belong to Bowen Marsh and the stewards. The show fused Thorne with that conspiracy to give Jon’s murder a familiar face — dramatically efficient, and a real change: the books’ betrayal comes from the Watch’s cautious middle, not its old grudge.
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.