Balrogs (/ˈbælrɒɡ/ ⓘ) are a species of powerful demonic monsters 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 Company of the Ring encounter a Balrog known as Durin's Bane in the Mines of Moria. Balrogs appear also in Tolkien's The Silmarillion and his legendarium. Balrogs are tall and menacing beings who can shroud themselves in fire, darkness, and shadow. They are armed with fiery whips "of many thongs",[T 1] and occasionally use long swords. In Tolkien's later conception, Balrogs could not be readily vanquished—a certain stature was required by the would-be hero. Only dragons rivalled their capacity for ferocity and destruction;[T 2] during the First Age of Middle-earth, they were among the most feared of Morgoth's forces. Their power came from their nature as Maiar, angelic beings like the Valar, though of lesser power. Tolkien invented the name "Balrog", providing an in-universe etymology for it as a word in his invented Sindarin language. He may have gained the idea of a fire demon from his philological study of the Old English word Sigelwara, which he studied in detail in the 1930s. Balrogs appear in the film adaptations of The Lord of the Rings by Ralph Bakshi and Peter Jackson, in the streaming series The Rings of Power, and in computer and video games based on Middle-earth.