House Karstark
A northern house of distant Stark blood, founded by a younger son of Winterfell an age ago, holding the grim keep of Karhold in the far northeast.
The fuller tale
House Karstark began as a branch of House Stark itself ÔÇö founded, the story goes, by a younger son of Winterfell generations back who was granted lands in the North's bleak eastern reaches rather than a claim on the seat he'd never inherit. Karhold has flown the black sunburst on white ever since, distant enough kin to the Starks that the family has never stopped considering itself Stark by blood first and bannerman second, an ambiguity that matters more than either side likes to admit once war forces the question.
Rickard Karstark's grief becomes the fault line that cracks Robb Stark's northern alliance from within. Two of his sons die at the Whispering Wood fighting Jaime Lannister's forces, and when Rickard finds a pair of young Lannister hostages in the camp and murders them in blind retaliation, Robb is left with an impossible choice between the law he has sworn to uphold and the bannerman whose grief, however criminal its outlet, he understands completely. Robb executes him himself, the same way his father would have ÔÇö and loses the Karstark levies at the exact moment the war can least afford it, one honest sentence pried loose from the alliance that might have saved the Starks from what came at the Twins.
What the execution costs Robb is not merely swords but a lesson about kinship the North does not easily forgive being ignored: the Karstarks are Stark blood by their own founding legend, and killing one of them for avenging his sons reads, to the bannermen watching, less like impartial justice than like a king choosing hostages over his own cousins. The half of the Karstark host that marches home in disgust rather than stay under Robb's banner is a smaller wound than the Red Wedding, but it opens well before that wedding, and it never fully closes.
The page and the screen
The books extend House Karstark's story well past Rickard's execution in a subplot the show has no room for: his daughter Alys Karstark, facing a forced marriage designed to seize her inheritance out from under her, flees to the Wall for protection and ultimately marries a wildling chieftain, Sigorn of the Thenns, in a match Jon Snow brokers to bind the Karstark lands to an ally rather than an enemy. It is an entire late-book strand of Northern politics ÔÇö succession, coerced marriage, an unlikely wildling alliance ÔÇö that never makes it to the screen.
