Race of evil fire-demons in J. R. R. Tolkien's Middle-earth

A Balrog is a powerful fictional monster in J. R. R. Tolkien's Middle-earth. One first appeared in print in his high fantasy novel The Lord of the Rings, where the Fellowship of the Ring encounter one known as Durin's Bane in the Mines of Moria. Balrogs appear also in Tolkien's The Silmarillion and other posthumously published books. Balrogs are tall and menacing beings who can shroud themselves in fire, darkness, and shadow. They are armed with fiery whips "of many thongs", and occasionally used long swords.