Smaug was a fire drake of the Third Age, considered to be the last "great" dragon to exist in Middle Earth. Smaug was drawn towards the enormous wealth amassed by the Dwarves of the Lonely Mountain during the reign of King Thror, and laid waste to the neighboring city of Dale and captured the Lonely Mountain, driving the surviving Dwarves into exile.

For almost two hundred years, Smaug hoarded the Lonely Mountain's treasures to himself, staying within the mountain, until a company of Dwarves managed to enter the Lonely Mountain and awaken him from hibernation. Correctly believing that the dwarves had received assistance from the men of Lake-town in entering the Lonely Mountain, Smaug left the mountain to wreak destruction upon Lake-town, nearly decimating it before being slain by Bard the Bowman.