Later on, when the Freys proposed a marriage between one of Lord Walder's daughter and Edmure, and Edmure refused, Brynden was openly aggressive in his insistence that Edmure go through with it. Ultimately Brynden, for all his faults, was a good man in his own right. That added to the conflict he felt of what was the right thing to do: whether to send men to Sansa or not." Brynden Tully gave himself the nickname ‘Blackfish’. Clive Russell, who portrayed Brynden "Blackfish" Tully in the series, spoke about his character's encounter with Brienne of Tarth, in an interview with IGN, noting "Brienne represented for him his young self, a person of integrity, a soldier of integrity, trying to do the right thing. After one such quarrel with his elder brother, when Lord Hoster called him the "black goat of the Tully herd", Ser Brynden pointed out that their sigil was a fish, so he took the name "Blackfish", and changed the color scheme of his personal sigil to a jumping black trout (which is normally silver in the Tully sigil). He even remarked that he would probably make a fool of himself as he hadn't fought with a sword in years. He is clean-shaven, and his face is craggy and windburnt, his features lined and weathered. He leads Brienne and her squire As the Freys and Lannisters celebrate their retaking of Riverrun at the Twins, Lord Walder gloats about the Blackfish's death at the hands of common foot soldiers. Ryman Frey and Jaime try to parley with Brynden, with Jaime offering Brynden to join the Night's Watch where Jon Snow is Lord Commander (in the books, the parley takes place before the By the point the books have reached, Brynden's current whereabouts are unknown.
"He asked me to stop calling myself "Blackfish". Following the Red Wedding, Ryman Frey leads two thousand spears to take Riverrun, reinforced by Lannister troops led by Ser Daven Lannister, and the forces of some of the Riverlords that bent the knee after the Red Wedding. The nickname caught on, and Brynden became … As the younger brother of Hoster, Lord Paramount of the Riverlands, Brynden was certainly one of the more eligible bachelors in Westeros. Later, in his final moments, he expressed regret that he ran once before at the Red Wedding, and resolved to die fighting against the men invading his home. Why is he called Blackfish?
He is a seasoned warrior, a veteran of half a hundred battles, and precise in his movements. Normally the Tully sigil is a silver trout, but for Brynden it is a black trout. Later, Brynden coldly accosted Edmure for his vainglorious blunder at the Stone Mill. He has bushy eyebrows and laughing eyes of deep blue.A kind man with the patience to listen, Brynden is also a blunt and stubborn man who does not care what others think. Others speculate that Brynden may have loved Minisa Whent, but after she married his older brother Hoster, he refused to ever love again. It’s a joke that Brynden appropriated for himself. Brynden anticipates the siege.