Ser Brynden Tully is a knight of House Tully and the younger brother of Lord Hoster Tully, with whom he has a long running feud. He was the knight of the Bloody Gate in the Vale of Arryn, and later became Warden of the Southern Marches under King Robb Stark.
Brynden is described as tall and lean, with grey hair that used to be the traditional auburn of House Tully. His face is lined and weathered, with bushy eyebrows above bright blue eyes. As an outrider he wears mail or leather, and has a clasp for his cloak shaped like a black fish.
Brynden takes the words of his house to heart and aims to be dutiful, honourable and just. He deeply cares for his nephew and his nieces, and is the first person that they would visit if they had a problem in their youth. When Lysa Arryn gets married he leaves with her. This may be a symbol of how much he cared for her.
Brynden squired for a Lord of House Darry in his youth and, when he came of age, he would be knighted. He would make a name for himself in the War of the Ninepenny Kings fighting alongside legendary knights like Ser Barristan Selmy. He would return to Riverrun a war hero, but would fall out with his brother when Brynden refused to wed a girl of House Redwyne. It was this incident that earned him the nickname Blackfish.
A Game of ThronesEdit
Brynden meets Catelyn Stark after she rides through the mountains to reach the Vale with Tyrion Lannister as her captive. Brynden believes that the Vale should offer aid and men to The Riverlands, however Lysa disagrees so Brynden resigns his post to leave with Catelyn. He sails with her to White Harbor, and then on to Moat Cailin, where he first meets his great-nephew Robb Stark.
Brynden is named leader of the outriders by Robb, and as such sits on his war councils. When they reach the Riverlands he leads combats against the Lannister outriders under the command of Ser Addam Marbrand. He successfully protects the knowledge of Robb crossing the Green Fork from Lannister ears, allowing for him to catch Ser Jaime Lannister by surprise at both the Battle of the Whispering Wood and the Battle of the Camps
A Storm of SwordsEdit
Brynden is present at the funeral of his brother Hoster. He takes up the bow and sets the funeral boat alight after his nephew misses three times, distracted by grief. By now Hoster has reconciled with his brother, uniting again over Hoster's deathbed.
He does not go north with Robb to attend the wedding of Lord Edmure Tully and Roslin Frey, instead staying at Riverrun to hold it in Robb's absence. As a reward for his contributions in the War of the Five Kings he is made Warden of the Southern Marches.
A Feast for CrowsEdit
After the brutal murder of Robb and Catelyn at the Red Wedding Brynden refuses to bend the knee to Joffrey I Baratheon or, after Joffrey's death, Tommen I Baratheon. He is besieged in the castle by a force consisting of House Frey, under the command of Ser Ryman Frey, House Lannister, under the command of Daven Lannister and an assortment of surrendered riverlords, but Brynden still refuses to surrender either the castle or Queen Jeyne Westerling, despite the threats of Edmure being hanged.
Jaime Lannister is sent to lift the siege and bring the Riverlands back under the King's peace. He parleys with the Blackfish, but only so Brynden can hear why he betrayed Catelyn and see that the Kingslayer has been maimed. He once again refuses to surrender the castle, even when Jaime says that he will let him take the black and go to The Wall. After Edmure surrenders the castle to Jaime Brynden manages to escape by swimming under a portcullis and into the Trident. He is labeled an outlaw after this incident.