A Storm of Swords
Errok is part of Jarl's group of raiders who climbs the Wall to take Castle Black from behind. He leads a group of four raiders to the top of Wall. After Jarl's death, Errok follows Styr's commands. Together with Del, he goes ahead to scout the ruins of Queenscrown. When he returns to the other raiders, he reports that there's an old man with a horse present in the town.