Glaurung is the dragon killed by Túrin, whose sister is Nienor, in J.R.R. Tolkien’s legendarium.
Glaurung appears in the First Age story later known as The Children of Húrin. He is called the Father of Dragons and serves Morgoth, using physical force and powerful deception against the people of Túrin’s family. His speech and hypnotic influence make him especially dangerous among Tolkien’s dragons.
Túrin finally kills Glaurung with his black sword, Gurthang, as the dragon crosses a ravine. The victory does not end the tragedy surrounding Túrin and Nienor, because Glaurung has already manipulated events and concealed crucial truths from them.
Glaurung is distinct from Smaug, the dragon of The Hobbit, and Ancalagon, the enormous winged dragon associated with the War of Wrath. Those dragons belong to different episodes of Tolkien’s mythology.