In the hobbit, the great goblin is the king of the goblins under the misty mountains. He is killed by Gandalf in the original book, and the persecution by the goblins afterwards leads to Bilbo's encounter with Gollum. As the company continues their adventures, the goblins seek revenge for their fallen leader, and march to the lonely mountain with an army of goblins and wargs, originating the final battle in the story