Bolg of the North was the son of Azog, the Orc of Moria who murdered Thrór and was killed in turn by Dáin at the Battle of Azanulbizar.1,2
The goblins of the northern mountains had been roused to vengeance by the death of the Great Goblin at Gandalf's hands, and had been gathering ever since. When word came that Smaug had fallen, they marched, with Wargs beside them and a cloud of bats overhead.1
In 2941 Bolg led the host of goblins and wolves that descended on the Lonely Mountain after Smaug's death. Gandalf brought the news of their coming to the Men, Elves and Dwarves who were on the point of fighting one another over the dragon's hoard, and turned them into allies in the Battle of Five Armies.1,3
Bolg fought surrounded by a bodyguard of huge goblins armed with scimitars of steel, and for much of the day the battle went his way. It turned when Beorn came, alone and in the shape of a great bear. He broke through the bodyguard and crushed Bolg himself, and the goblin army broke and fled.1,4
On screen
Where the best-known adaptation departs from the books. Nothing in this section is evidence for the books themselves.
In Jackson's Hobbit films Bolg leads the Orcs who hunt the company, kills Kíli in the Battle of the Five Armies, and is killed by Legolas. In the book it is Beorn who crushes him.5,1
Sources
Citations name the chapter rather than the page, so they work in any edition. The colour of each note shows what kind of source it is.
- Published story The Hobbit and The Lord of the Rings as Tolkien published them.
- Appendices Tolkien's own appendices to The Lord of the Rings.
- Adaptation Films and other adaptations. Never evidence for the books.
- Published story The Hobbit, ch. 17, “The Clouds Burst”
- Appendices The Lord of the Rings, Appendix A, III, “Durin's Folk”
- Appendices The Lord of the Rings, Appendix B, “The Third Age”
- Published story The Hobbit, ch. 18, “The Return Journey”
- Adaptation Peter Jackson's film trilogy (2001–2003), The Hobbit trilogy (2012–2014)