Robb Stark: The King in the North
Undefeated on the battlefield; a mess everywhere else. The Young Wolf just torpedoed a crucial alliance by breaking his promise to marry the daughter of a key nobleman. He's estranged from his mother Catelyn because she freed his captive Jaime Lannister from prison, leaving his bannermen furious; learning he's an oathbreaker won't make them any happier. And whatever went down at Winterfell between Theon Greyjoy's Ironmen and the army Lord Bolton's bastard son brought to recapture it, it destroyed the place in its wake, leaving Robb without a home base, and without his kid brothers. He'd better hope his warrior win streak remains unbroken.