"The Wargs came ravening and down came the bodyguard of Bolg, goblins of huge size with scimitars of steel."
During the Battle of the Five Armies, Thorin Oakenshield attacked them and while driving off the wargs in that area, could not break through the bodyguards, which means they were literally the ones to kill one of the greatest dwarven warriors and kings of all time. When Beorn came, he scattered them and crushed Bolg. After their king's death, few, if any, survived the remnant of the battle and it's aftermath.
While a type of Orc, the exact breed is unknown. While they might have simply been large Goblins, they were probably originally meant to have been Hobgoblins. Later, when Tolkien came up with the Uruk-hai and apparently abandoned the idea of hobgoblins, they were likely instead meant to have been some of the Mordor Uruks that inhabited Moria.
Portrayal in adaptionsEdit
Peter Jackson's movie trilogyEdit
These Orcs unofficially appeared in Peter Jackson's The Hobbit: The Battle of the Five Armies as Orcs Berserkers. One of them is slain by Dwalin when he attempted to kill Bilbo, while another one was sent to kill Thorin Oakenshield, but Legolas saved the dwarven king by stabbing the Orc in the stomach with Thorin's sword, Orcrist. Many more of those Orcs were slain on Ravenhill.
Bolg's bodyguards appeared in The Hobbit (2003 video game) at the level of Dreamworld.