Smaug was the dragon who guarded the treasure beneath the Lonely Mountain in J.R.R. Tolkien’s The Hobbit.
Smaug seized Erebor, the Dwarves’ kingdom under the Lonely Mountain, and drove its inhabitants into exile. His hoard included the Arkenstone and vast wealth accumulated by the Dwarves. Bilbo Baggins enters the mountain during Thorin Oakenshield’s quest and speaks with Smaug, learning about the dragon’s habits and discovering a vulnerable patch in his armor.
The dragon’s weak point is later revealed to Bard the Bowman, who uses the Black Arrow to kill him. Smaug’s death triggers the Battle of the Five Armies because several groups seek control of the treasure after the dragon is gone.
Smaug is distinct from Tolkien’s earlier dragons Glaurung and Ancalagon, who belong to the First Age stories. Smaug is the principal dragon of The Hobbit and one of Tolkien’s best-known villains.