Keeper of the Dungeons

A Gundabad Orc Chieftain, later known as the Keeper of the Dungeons, was present at the Battle of Azanulbizar.
He fights against the Dwarves of the Lonely Mountain. After being defeated by Dwalin, the Orc brute survived his wounds and went into hiding in Mount Gundabad. Years later, he is summoned to Dol Guldur before the battle against the Dwarves, Men, and Elves in the Lonely Mountain and Dale, but unlike his comrades, he stayed in the fortress and kept watch on Gandalf who had been imprisoned and defeated by Sauron. He received order from Sauron to execute the wizard and confiscate the Ring of Fire (Extended Edition only), throwing Gandalf's cage across the tower. Before the orc could cut the ring off and kill the wizard, Galadriel arrived at the old fortress and killed him.
The Orc Chieftain was originally intended to be Bolg, but the decision to change the character's identity was made before the release of the second film in the trilogy.