After the Fall of Mount Gundabad, the orcs of the Northern Wastes and Iron Mountains--issued forth against the Dwarves of Gundabad. The orcs that had laid in wait in the depths of the earth and snow, heard Sauron's call to arms and Gundabad was hard pressed and eventually fell.
With the establishment of this realm, the orcs spread to what became known as Goblin Gate and Mount Gram. They even expanded their dwellings throughout the Iron Mountains--with this, the Goblins were easily able to traverse without detection and could often spring up on their foes.
Grarfim and his father did this, travelling from Mount Gram and through the Iron Mountains--their forces fell upon the Gardens of the Entwives. Though many Northmen, Donath and Entwives defended the location--Grarfim and his father were successful with their allies from Rhûn, Khand, and the Withered Heath in erasing the Gardens off the face from the earth.
After the loss of his father and the coming of Elves, Men, and Dwarves of the Last Alliance, Grarfim led his people back into the Iron Mountains and back home, for the battle had cost his troops dearly and the Misty Mountain orcs could not see continue fighting with the Northmen and Donath, thus they tactically withdrew.
Grarfim eventually passed. But his sons and grandsons would reign in his stead. In fact, Golfimbul was said to be descended from him.