With the death of Lord John Arryn, the Eyrie, seat of House Arryn, is now ruled by Lysa Arryn. She is the mother of Robin Arryn, the future Lord of the Vale. Lysa Arryn is the sister of Catlyn Stark, and she blames House Lannister for the death of her late husband. Additionally, Eddard Stark was fostered in the Eyrie. When King Robert rebelled, it rose with him and Lord Stark. With the Stark traitor's execution, the houses of the Vale have called upon Lady Arryn to join the Young Wolf in making war upon your grandfather. According to Lord Tyrion Lannister, Lady Arryn is extremely scared of any danger befalling Young Robin and refuses to enter the fray in order to protect him. The Houses of the Vale will stop never join war on our side and must be kept out of the war at all costs.