Arnolf Karstark by [http://dragonman14x.deviantart.com/gallery/
A Dance with Dragons (Appears)|
The Winds of Winter (Appears)
Arnolf is gaunt, crooked and bent from age and walks with a cane. His left shoulder is half a foot higher then his right. He has a scrawny neck, squinty grey eyes, and is a few white hairs away from complete baldness. His teeth are yellow and he was a forked ragged grey and white beard. According to Theon Greyjoy he is "a poor excuse of a man".
A Dance with Dragons
After Stannis Baratheon sent a declaration of his arrival in the North and a demand for fealty, Arnolf was the only to respond favorably to him, pledging Stannis his support. It was revealed however that Arnolf only responded favorably in hopes that when the Iron Throne heard they would execute Harrion Karstark who was still a hostage of the Lannisters, that way Alys Karstark would be the heir and Arnolf would then force her to marry his son Cregan Karstark to claim Karhold. In addition Arnolf worked in secret with Roose and Ramsay Bolton to try and lure Stannis north to attack the Dreadfort where Arnolf's force would meet up with Stannis's army and then turn its cloak as the siege began. Roose promised him a full pardon for this service for the Lannisters.
However under Jon Snow's advice Stannis did not attack the Dreadfort but Deepwood Motte instead, thus spoiling the plan. Arnolf had his army meet up with Stannis when they marched on Winterfell. During the battle Arnolf's host would turn on Stannis. However this plot was revealed to Jon Snow by Alys Karstark who had fled to the Wall to escape the arranged marriage. Snow sent a message to Stannis to warn him of Karstark's treachery.
The Winds of Winter
The message arrives in time, Stannis has Arnolf his son and three grandsons brought before him on the pretext of breaking there fast. Arnolf Karstark upon entering notices the chained Theon Greyjoy in the corner and released knows that Stannis is aware of his planned treachery.
Stannis knights surround the five Karstarks, two of his grandsons attempt to resist and are badly injured but Arnolf does not put up a fight. Stannis has vowed that all five will die but whether quickly or by fire will depend on their cooperation