Deep Goblins, also known as Goblins of the Deep or Orog, were the descendants of lesser Goblins of the First Age who had retreated completely from sunlight under the earth to the vast subterranean realms of the Underdeeps.
Taking over MoriaEdit
On TA 2994, a band of these Goblins overrun the dwarven colony in Moria. After killing all the Dwarves in Moria, the Goblins of the Deep named themselves the "Moria Goblins" after they took over the mines.
War of the RingEdit
When the Fellowship passes through the abandoned Dwarf city of Dwarrowdelf, Pippin accidentally alerts the Goblins to their presence, causing a fight to break out in the Tomb of Balin. In this instance, their main weapon appears to be a Cave troll, which has to be brought down by the whole Fellowship, but the entire force is wiped out by the end of the battle. However, the skirmish allows a much larger force of Goblins to close in on the Fellowship, who flee to the Bridge of Khazad-dûm. Unfortunately for them, even more Goblins intercept them in one of Dwarrowdelf's great halls, emerging from cracks in the floor and holes in the ceiling to aid their comrades.
Trapped in a near-literal sea of Goblins, the Fellowship could only prepare for death, but the evil creatures suddenly paused as a menacing roar echoed in the distance. As a distant hall lit with a fiery orange glow, the Goblins inexplicably fled in all directions, leaving the Fellowship to wonder at their fortune — as well as at what was coming next: Malraugin.
Deep Goblins were described as a different breed of Goblins. They are also a very green colour compared to the varied colour of goblins elsewhere, they also had larger pointier ears and huge bulbous eyes, as expected from creatures that live in the dark.