travel to Winterfell to aid Robb Stark in his campaign against the Lannisters. His intelligence and caution sees him given command of part of the Northern host when the army splits up at the Twins, and he leads the attack on Tywin Lannister's army in the Battle of the Green Fork. The battle ends in a Lannister victory and Roose retreats with the survivors to the causeway of Moat Cailin. In the novels, it is implied that Roose battled with Tywin, not just to distract him and allow Robb to pass, but also to weaken the houses he was given command over: in the battle, Tyrion sees Bolton soldiers in the retroguard, while the vanguard is composed entirely with soldiers of the other Northern Houses. While the two vanguards clash, it also starts to rain arrows over both sides. While Tyrion doesn't know from where the arrows came from, it can be assumed that they were fired by Roose, since Tywin is not the type of person that wastes men and arrows. A Clash of Kings To form an alliance with House Frey, Roose is offered by Lord Walder Frey one of his female family members hand in marriage, as well as offering the prospective bride's weight in silver for her dowry. Roose chooses "Fat" Walda Frey, the fattest female member of House Frey. He also makes an alliance with the Brave Companions, Essosi sellswords employed by Tywin, to help the Northerners capture Harrenhal from the Lannister force occupying it. After capturing Harrenhal Roose takes Arya Stark as a servant, mistaking her for a commoner. In a conversation Arya casually hears, Roose and the Freys point that Robb cannot win the war, since Tywin formed an alliance with High Garden. It is assumed that Roose and the Frey started to plan their betrayal, at this point. A Storm of Swords While in Harrenhal, Roose weakens Robb's army over and over again, sending other lords on suicidal missions. Hoat brings Jaime Lannister to Harrenhal, having cut off Jaime's hand in hope of blaming Roose and preventing the Boltons allying with the Lannisters. Roose has Jaime sent back to King's Landing after Jaime assures Roose that he will not blame him. Roose then travels to the Twins for Edmure Tully's wedding to Roslin Frey, but at the wedding the Freys turn on the Starks and Roose personally kills Robb Stark. It is