Balrog

Balrogs are Maiar — members of the Ainur of the Maia order — who were corrupted into the service of Melkor (later called Morgoth) before and during the shaping of the World. Tolkien's texts and editorial notes describe Melkor's corruption of some Maiar into instruments of terror and war; these corrupted Maiar became Balrogs, serving as Morgoth's elite warriors and torturers during the wars of the First Age and later. Tolkien's drafts vary on number and details (earlier drafts portrayed them more numerous and more easily destroyed; later notes propose they were far fewer — one marginal note suggests "at most seven" — and correspondingly more powerful). After Morgoth's defeats, some Balrogs remained hidden in deep places of the world (for example, Durin's Bane in the depths of Moria), re-emerging in later Ages.

Descriptions in Tolkien's writings present Balrogs as tall, menacing figures often shrouded in shadow and flame, with an inner dark humanoid shape visible within a great shadow (Gandalf's account at Khazad-dûm: "like a great shadow, in the middle of which was a dark form, of man-shape maybe, yet greater"). They are associated with fire—flames about the body and furnaces of light in their eyes—and with weapons such as many‑thonged whips of fire, flaming swords, and in some drafts axes, maces, or iron mail. Tolkien's accounts vary on particulars (size estimates range across drafts; some individual Balrogs are described as larger than men, and at least one draft gives a specific larger height for a named Balrog), and imagery such as wings appears in some texts but is debated as literal versus figurative across revisions.

Balrogs can cloak themselves in fire, shadow, and darkness and wield fiery whips (described as "of many thongs") and other burning or black weapons in combat. As corrupted Maiar their power derives from their metaphysical nature as Ainur — in Tolkien's later conception this means they are not merely mortal monsters but spirits whose physical manifestation may be destroyed while their underlying metaphysical status remains of the Maia order. They were employed by Morgoth as elite fighters and torturers and were formidable in battle; Tolkien's later notes indicate that beings of Maia order (for example Gandalf or other powerful Maiar) were required to defeat them reliably. Earlier drafts present them as more numerous and more readily vanquished, illustrating an evolution in Tolkien's portrayal from many demonic foes to a smaller number of exceptionally fearsome fallen spirits.