Rickard Karstark
Lord of Karhold, a proud, grim northern bannerman of distant Stark blood, who marches his sons to war under the direwolf banner.
A soul born at Karhold, sworn to House Karstark.
The fuller tale
Season Two
One of Robb's greatest strengths on paper, the lord who brings the largest northern host to the war and sits close at every council that matters. His son stands guard over Jaime Lannister at Riverrun as a courtesy nobody thinks twice about, until Jaime strangles the boy with his own chain during a bungled escape attempt. Karstark buries a son and keeps fighting, but the grief does not go anywhere; it just waits for a second one to land on top of it.
Season Three
By the time Catelyn frees Jaime Lannister without her son's leave, Karstark has already lost two sons to the war and has nothing left to trade for patience. He murders two Lannister boys being held hostage at Riverrun, cousins of Jaime's, killing them in their cells as payment nobody asked him to collect. Robb tries him for murder in front of the whole camp and executes him himself rather than pretend the law bends for grief, and half the Karstark host rides home in disgust the same day — the last northern lords Robb can afford to lose, gone because he would not look away from what one of them did.
How it ends for them
On the screen. Beheaded for murder (S3·E5)
He butchered two captive Lannister boys in their cell to answer his sons' deaths, and dared his king to do something about it. Robb Stark took his head at Riverrun with his own hand — justice that cost him half his army.
On the page. Executed by the King in the North (ASOS, ch. 21)
He broke into Riverrun's cells and butchered two Lannister squires, then dared his king to answer for it. Robb took his head in the rain in Riverrun's godswood with his own hand — and the Karstark strength rode home.
Robb Stark held the trial in his own person, as Ned had taught him: the man who passes the sentence swings the sword. For the murder of two captive boys, Rickard Karstark was condemned by his king — over the pleading of nearly every adviser Robb had, all of them making the same argument, that the Karstarks were half his infantry and dead lords pay no debts. Robb hanged the seven who did the deed and took Rickard's head himself, in the show at a block in the rain, in the books in Riverrun's godswood, where it took more than one stroke. The condemned man's last words were the same in both: a curse, and a title revoked — kill me and be cursed, you are no king of mine. The Karstark strength marched home the next morning, and every historian of the war, in-world and out, marks the same entry: justice done perfectly, and the cause it belonged to poorer by half an army. Walder Frey merely finished what Riverrun's headsman's-block began.
Their chapters, book by book
A Storm of Swords 1 chapter that name them
Where the page and the screen part
The show compresses the Karstark ledger — one son dead in the Whispering Wood instead of two, unnamed Lannister boys instead of the books' Tion Frey and Willem Lannister, murdered in Riverrun's cells — but keeps the moral shape intact. The books extend the aftermath in ways the show skipped entirely: Rickard's heir Harrion sits a Lannister prisoner, his uncle Arnolf schemes to betray Stannis and steal Karhold, and his daughter Alys flees to the Wall to escape a forced marriage, giving Jon Snow one of A Dance with Dragons' warmest subplots. The show's sequel to the Karstark grudge is simpler and colder: the house rides with Ramsay Bolton at the Battle of the Bastards, and a later generation's small children stand in Winterfell's hall to be forgiven. Two tellings, one lesson — the wound Robb dealt at Riverrun never stopped bleeding.
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.