Their main weapon is terror, though in their pursuit of the Ring-bearer Frodo Baggins, their leader uses a Morgul-knife which would reduce its victim to a wraith, and they carry ordinary swords.
[1] Their sight worked differently, too: "They themselves do not see the world of light as we do, but our shapes cast shadows in their minds, which only the noon sun destroys; and in the dark they perceive many signs and forms that are hidden from us: then they are most to be feared.
[T 14] They learn that the Ring has passed to Bilbo's heir, Frodo, and hunt him and his companions across the Shire; the hobbits hear snuffling, and sometimes see them crawling.
[T 6] During their assault, they mentally command Frodo to put on the One Ring; while wearing it, he sees them as pale figures robed in white, with "haggard hands", helmets and swords.
At length even the stout-hearted would fling themselves to the ground as the hidden menace passed over them, or they would stand, letting their weapons fall from nerveless hands while into their minds a blackness came, and they thought no more of war, but only of hiding and of crawling, and of death.
[T 26][T 27] During the Battle of the Pelennor Fields, the Lord of the Nazgûl uses magic, including Grond, a battering-ram engraved with evil spells, to break the gates of Minas Tirith.
Merry's surreptitious stroke with an enchanted Barrow-blade brings the Nazgûl to his knees, allowing Éowyn, the niece of Théoden, to drive her sword between his crown and mantle.
[T 30] When Frodo claims the Ring for his own in Mount Doom, Sauron, finally realizing his peril, orders the remaining eight Nazgûl to fly to intercept him.
The medievalist Marjorie Burns compares the fell beast to the Poetic Edda's flying steed Sleipnir, "Odin's eight-legged otherworldly horse".
The horseman in dark clothes in the early chapter "Three is Company"[T 16] was originally Gandalf; in 1938, Tolkien called the figure's transformation into a Black Rider "an unpremeditated turn".
[8] He quotes the "Nine Herbs Charm" from the Lacnunga, an Old English book of spells:[8] against venom and vile things and all the loathly ones, that through the land rove, ... against nine fugitives from glory, against nine poisons and against nine flying diseases.
Jason Fisher, writing that "all stories begin with words", takes up Edmund Wilson's "denigrating dismissal" of The Lord of the Rings as "a philological curiosity", replying that to him this is "precisely one of its greatest strengths".
[11] Fisher notes that the word has a history in folktale and fantasy including usage by the Brothers Grimm, William Morris, and George MacDonald.
[10] Shippey writes that the Nazgûl function at different stylistic levels or modes (as categorised by Northrop Frye in his Anatomy of Criticism) in the story.
But, Shippey notes, the level rises from the romantic, with heroes taking on the Black Riders, to the mythic, giving as example the assault of Minas Tirith.
[13] Yvette Kisor, a scholar of literature, writes that while the Ringwraiths and others (like Frodo) who wear Rings of Power become invisible, they do not lose any of their corporeality, being present as physical bodies.
Little by little, in his view, Tolkien increases the reader's insight into their nature, starting with Black Riders who are "spies more human than diabolical", rather than developing their character.
He writes that the progressive revelation of their capabilities, and their "escalation of steeds" from horses to fell beasts, builds up in the reader's mind an "increasingly infernal vision".
[17] She comments that the Black Breath, contracted by "excessive proximity" to a Nazgûl, seems to be a "spiritual malady" combined with "fear, confusion, reduced levels of consciousness, hypothermia, weakness and death.
"[17] Faramir, on the other hand, who was thought to be suffering from the Black Breath, she diagnoses as most likely exhaustion with heat stroke, combined with "psychological distress" and pain, as his symptoms were quite different.
[20] Garth comments that these names "anchor him in the primal night" of Tolkien's giant spiders, the Black Breath, the fog on the Barrow-downs, and the terror of the Paths of the Dead.
He adds that this fog of terror may ultimately derive from Tolkien's First World War experience "of smoke barrages, gas attacks and 'animal horror' on the Somme.
"[20] Earlier, in his 2003 book Tolkien and the Great War, on the other hand, Garth merely notes the "Black Breath of despair that brings down even the bravest" as one of several elements of The Lord of the Rings which "suggest[s] the influence of 1914–18".
[22] The Inklings scholar Ariel Little writes that Tolkien explicitly opposes the enslaved Nine Riders with the Nine Walkers, the free Company of the Ring.
He adds that the evil characters in The Lord of the Rings are characterised by infighting, as among the Orcs, lack of harmony, and "hate-filled discord", forming an "anti-community".
[2] He writes that even when the Company splits up into smaller groups, it is not destroyed: far from it, Frodo and Sam sustain each other through their arduous journey, their friendship deepening with time; Merry and Pippin supporting each other; Aragorn, Legolas, and Gimli acting as a team, all continuing to function as communities.
[27] The 1991 Russian television play Khraniteli features a group of Nazgûl galloping through a snowy pine forest; they wear black cloaks, with glimpses of red equipment.
In the first film, Radagast briefly encounters the Witch-king while investigating Dol Guldur, and gives the Nazgûl's Morgul dagger to Gandalf to present at the White Council as proof of their return.
This confirms the Necromancer's identity as Sauron, as the Nazgûl appear alongside their master in the third film in spectral forms wearing Morgul armour and fight Elrond and Saruman before being driven away by Galadriel.
[37] For the expansion to its real-time strategy game The Lord of the Rings: The Battle for Middle-earth II, The Rise of the Witch-king, Electronic Arts invented the name Morgomir for one of the Nazgûl.