Balrog

Balrog refers to a class of formidable beings in J. R. R. Tolkien's Middle-earth legendarium. They are described as corrupted Maiar — lesser spirits of the Valar — who were corrupted by Morgoth, the first Dark Lord, and who served him in the First Age. The name is Sindarin; it is commonly rendered as demon of power or fiend of might, although Tolkien never provides a formal translation in the text.

Balrogs are portrayed as beings of fire and shadow, often tall and cloaked, with a fiery presence rather than a fixed, humanoid form. They typically wield weapons such as a whip of flame and, at times, a sword. Their exact appearance and nature are left deliberately enigmatic, emphasizing their fearsome presence and power.

In the First Age, Balrogs were among Morgoth's most formidable servants and took part in many of the wars against the Elves and their allies in Beleriand. The best known Balrog encounter in Tolkien's mature writings is Durin's Bane, a Balrog that dwelt in the depths of Khazad-dûm (Moria) and terrorized the dwarves for generations until awakened and opposed by the Fellowship.

In The Lord of the Rings, Gandalf confronts a Balrog on the Bridge of Khazad-dûm. After a long duel through underground passages of fire and shadow, they fall into the chasm; Gandalf is believed dead and is later returned as Gandalf the White. The Balrog is defeated in the ensuing struggle, also perishing, though both are later said to have completed their mortal conflict.