Banak Brawnanvil was one of the dwarves of Mithral Hall who defended against the orcs led by Urlgen Threefist. He was the High Commander. In 1370 DR, during the battle with army of orcs commanded by King Obould Many-Arrows, he was hurt by a goblin spear. The weapon struck his back and broke his spine, leaving him without the use of his legs. He still had movement thanks to a wheelchair that was made for him by the gnome alchemist Nanfoodle Buswilligan. The dwarf was given control over Mithral Hall when Bruenor was not there.
Banak was King Bruenor Battlehammer's cousin, making him Bruenor's closest living relative.