Siege the King

From BoardGameGeek:

Two players are each given two throne cards and one king, which they place facedown in front of them in random order. Each has a defense rating of 10. Players start with a hand of five cards, taking turns to either play Attackers on an opposing castle card, or a defender on their own card. The goal is to reduce a castle card's defenses to zero, hoping that it's the king card, thereby conquering the kingdom and winning.