A skilled and experienced fighter who made his name during the War of the Ninepenny Kings, Ser Brynden Tully has proved invaluable to King Robb as an advisor and captain of the outriders. He is called the Blackfish after one of his many quarrels with his elder brother, Lord Hoster Tully. When Lord Hoster called him the black goat of the family, Ser Brynden laughed it off, suggesting that it was more appropriate for a Tully to be called the black fish. Lord Hoster and Ser Brynden were estranged after Brynden refused to marry a woman Lord Hoster had chosen for him and have reconciled only after Brynden came with Robb Stark to lift the siege of Riverrun, finding Lord Hoster on his deathbed.
Formerly Knight of the Bloody Gate, Ser Brynden left the service of his niece, Lady Lysa, after the death of Lord Jon Arryn and the attack of the Lannisters upon the riverlands.