Bolg was the orc leader at the Battle of the Five Armies. Bolg’s father Azog was killed by Dain Ironfoot at the Battle of Azanulbizar in 2799 of the Third Age. Bolg’s hatred of the Dwarves was rekindled when the Great Goblin was killed during an encounter with Thorin Oakenshield & Company in 2941. Bolg gathered an army of Orcs from throughout the Misty Mountains at their capital, Mount Gundabad. They marched eastward through the Grey Mountains with a host of Wargs and a cloud of bats overhead.
At the Lonely Mountain, Bolg led the Orcs and Wargs into battle with the Dwarves, Wood-elves, and Lake-men. He was surrounded by a bodyguard of huge Orcs with steel scimitars. Thorin Oakenshield tried to break through Bolg’s bodyguard, but he could not pierce their ranks and soon he was surrounded and later died of the wounds he received. Then the Eagles arrived and after them came Beorn in the shape of a bear. Bolg was slain by Beorn and the Orcs and Wargs were defeated.