Jason Mallister

Jason Mallister is the Lord of Seagard and the head of House Mallister. He is a loyal bannerman of House Tully.

During the Greyjoy Rebellion, Lord Jason led the a victorious defense of his ancestral seat of Seagard against an attack by the ironborn forces led by Rodrik Greyjoy and killed him.

In the books
In the A Song of Ice and Fire novels, Lord Jason Mallister is a loyal bannerman of House Tully. He has at least one son, Patrek Mallister. As a young knight, he was defeated by Prince Rhaegar Targaryen in a tourney at Storm's End. During the early stage of Robert's Rebellion, he attended the wedding of Eddard Stark and Catelyn Tully, giving them lavish gifts. He participated in the Battle of the Trident, slaying three of Prince Rhaegar's bannermen, thus avenging the death of his kinsman Jeffory Mallister, who had been killed under orders of the Mad King.

Lord Jason takes part in the Tourney of the Hand and later, during the War of the Five Kings, takes part in the Battle of the Whispering Wood and the liberation of Riverrun at the Battle of the Camps. He returns to Seagard after Robb Stark is declared the King in the North.