"You must be blind as well as maimed,Ser.Lift your eyes and you'll see that the direwolf still flies above our walls" Brynden to Jaime Lannister
Commonly known as the Blackfish, he does not like to suffer a fool. Ser Brynden serves his niece Lady Lysa Arryn as Knight of the Gate.His name was given by his brother Lord Hoster Tully as he refused all the marriage proposals he offered him being the Black Goat of House Tully.
During the War of the Five Kings he joins his grandnephew,Robb Stark's campaign in the South,resigning from his position on The Eyrie.A great veteran who participated in several wars including the War of the Ninepenny Kings;He became an important commander of the Stark forces fighting in the Battle of the Whispering Wood and the Battle of the Camps.For his military merits Robb named him Warden of the Southern Marches.
On the books he is not at the Twins at the time of the Red Wedding staying in Riverrun in preparation for the plan to retake Most Cailin from the Ironborn.He refused to surrender to the Lannister and Frey forces even when the other Riverlords bowed to the Iron Throne holding Queen Jayne Westerling,Robb's Widowed.Edmure threatened by Jaime broke the siege but The Blackfish scaped in time.
On the screen he assists the Red Wedding scaping the event promising vengeance on the Freys,at season 6 he died fighting the Lannister forces,death offscreen.