Silmarillion
The origins of the Ringwraiths is explained, along with some abilities.Of the Rings of Power and the Third Age wrote:'Men proved easier to ensnare. Those who used the Nine Rings became mighty in their days, great kings, sorcerers, and warriors of old. They obtained glory and great wealth, yet it turned to their undoing. They had, it seemed, unending life, yet life became unendurable to them. They could walk, if they would, unseen by all eyes in this world beneath the sun, and they could see things in worlds invisible to mortal men; but too often they beheld only the phantoms and delusions of Sauron. And one by one, sooner or later, according to their native strength and to the good or evil of their wills in the beginning, they fell under the thralldom of the ring that they bore and under the domination of the One, which was Sauron's. And they became for ever invisible save to him that wore the Ruling Ring, and they entered into the realm of shadows.'
Fellowship of the Ring
This will be a common theme of the Nazgûl, the ability of other beings to sense their presence and be affected negatively by it.Three is Company wrote:"I can hear a pony or a horse coming along the road behind," said Sam.
They looked back, but the turn of the road prevented them from seeing far. "I wonder if that is Gandalf coming after us," said Frodo; but even as he said it, he had a feeling that it was not so, and a sudden desire to hide from the view of the rider came over him....
The Black Breath, able to knock out a Hobbit cold. The range is unknown, but Merry was fairly close when he was hit with it.Strider wrote: ‘“I don’t know,” said Merry. “Neither brave nor silly, I think. I could hardly help myself. I seemed to be drawn somehow. Anyway, I went, and suddenly I heard voices by the hedge. One was muttering; and the other was whispering, or hissing. I couldn’t hear a word that was said. I did not creep any closer, because I began to tremble all over. Then I felt terrified, and I turned back, and was just going to bolt home, when something came behind me and I…I fell over.”
“I found him, sir,” put in Nob. “Mr. Butterbur sent me out with a lantern. I went down to the West-gate, then back up towards the South-gate. Just nigh Bill Ferny’s house I thought I could see something in the Road. I couldn’t swear to it, but it looked to me as if two men was stooping over something, lifting it. I gave a shout, but when I got up to the spot there was no signs of them, and only Mr. Brandybuck lying by the roadside. He seemed to be asleep. ‘I thought I had fallen into deep water,’ he says to me, when I shook him. Very queer he was, and as soon as I had roused him, he got up and ran back here like a hare.”
“I am afraid that’s true,” said Merry, “though I don’t know what I said. I had an ugly dream, which I can’t remember. I went to pieces. I don’t know what came over me.”
“I do,” said Strider. “The Black Breath.”’
This bears similar characteristics to a "blasting spell" much later in the book, though obviously without a giant battering ram.A Knife in the Dark wrote: ‘The figure by the door moved. In the dark without moon or stars a drawn blade gleamed, as if a chill light had been unsheathed. There was a blow, soft but heavy, and the door shuddered.
“Open, in the name of Mordor!” said a voice thin and menacing.
At a second blow the door yielded and feel back, with timbers burst and lock broken. The black figures passed swiftly in.’
Some of their abilities made explicit. Their senses are both more acute and restricted then normal human senses, and they can detect the presence of other people just as others can feel theirs.A Knife in the Dark wrote:‘“I was too careless on the hill-top,” answered Strider. “I was very anxious to find some sign of Gandalf; but it was a mistake for three of us to go up and stand there for so long. For the black horses can see, and the Riders can use men and other creatures as spies, as we found at Bree. 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. And at all times they smell the blood of living things, desiring and hating it. Senses, too, there are other then sight or smell. We can feel their presence – it troubled our hearts, as soon as we came here, and before we saw them; they feel ours more keenly. Also,” he added, and his voice sank to a whisper, “the Ring draws them.”’
Again the presence of the Nazgûl is detected before being seen, described as a cold sensation. The cold feeling too will be a common theme.A Knife in the Dark wrote:'Sam and Merry got up and walked away from the fire. Frodo and Pippin remained seated in silence. Strider was watching the moonlight on the hill intently. All seemed quiet and still, but Frodo felt a cold dread creeping over his heart, now that Strider was no longer speaking. He huddled closer to the fire. At that moment Sam came running back from the edge of the dell.
"I don't know what it is," he said, "but I suddenly felt afraid. I durstn't go outside this dell for any money; I felt that something was creeping up the slope."'
Same as above.A Knife in the Dark wrote:Over the lip of the little dell, on the side away from the hill, they felt, rather than saw, a shadow rise, one shadow or more than one. They strained their eyes, and the shadows seemed to grow. Soon there could be no doubt: three or four tall black figures were standing there on the slope, looking down on them. So black were they that they seemed like black holes in the deep shade behind them. Frodo thought that he heard a faint hiss as of venomous breath and felt a thin piercing chill. Then the shapes slowly advanced.
The attack on Weathertop, and what the Nazgûl look like in the wraith-world. Frodo's sword flickering red like fire seems to give some credence to the fact that the Blades of Westerness they got at the Barrow-Downs do have some sort of anti-Wraith magic made into them, considering they caused some of the Nazgûl pause. A pale-glowing sword or knife seems to be a common feature of Nazgûl 'spells', more of which we'll see coming up. Once more, fear felt in the presence of Nazgûl described in terms of coldness.A Knife in the Dark wrote:'Terror overcame Pippin and Merry, and they threw themselves flat on the ground. Sam shrank to Fordo's side. Frodo was hardly less terrified than his companions; he was quaking as if he was bitter cold, but his terror was swallowed up in a sudden temptation to put on the Ring...He shut his eyes and struggled for a while; but resistance became unbearable, and at last he slowly drew out the chain, and slipped the Ring on the forefinger of his left hand.
Immediately, through everything else remained as before, dim and dark, the shapes became terribly clear. He was able to see beneath their black wrappings. There were five tall figures: two standing on the lip of the dell, three advancing. In their white faces burned keen and merciless eyes; under their mantles were long grey robes; upon their grey hairs were helms of silver; in their haggard hands were swords of steel. Their eyes fell on him and pierced him, as they rushed towards him. Desperate, he drew his own sword, and it seemed to him that it flickered red, as if it was a firebrand. Two of the figures halted. The third was taller then the others: his hair was long and gleaming and on his helm was a crown. In one hand he held a long sword, and in the other a knife; both the knife and the hand that held it glowed in a pale light. He sprang forward and bore down on Frodo.
At that moment Frodo threw himself forward on the ground, and he heard himself crying aloud: O Elbereth! Gilthoniel! At the same time he struck at the feet of his enemy. A shrill cry rang out in the night; and he felt a pain like a dart of poisoned ice pierce his left shoulder. '
This is the first we hear of the Witch-King's 'invulnerability' against normal weapons, and the introduction of the Morgul-blades.Flight to the Ford wrote: ‘“Look!” he cried; and stooping he lifted from the ground a black cloak that had lain there hidden by the darkness. A foot above the lower hem there was a slash. “This was the stroke of Frodo’s sword,” he said. “The only hurt that it did to his enemy I fear; for it is unharmed, but all blades perish that pierce that dreadful King. More deadly to him was the name of Elbereth.”
“And more deadly to Frodo was this!” He stooped again and lifted up a long thin knife. There was a cold gleam in it. As Strider raised it they saw that near the end its edge was notched and the point was broken off. But even as he held it up in the growing light, they gazed in astonishment, for the blade seemed to melt, and vanished like a smoke in the air, leaving only the hilt in Strider’s hand. “Alas!” he cried. “It was this accursed knife that gave the wound. Few now have the skill in healing to match such evil weapons. But I will do what I can.”’
Once more, Nazgûl fear associated with coldness.Flight to the Ford wrote:He could see them clearly now: they appeared to have cast aside their hoods and black cloaks, and they were robed in white and grey. Swords were naked in their pale hands; helms were on their heads. Their cold eyes glittered, and they called to him with fell voices.
Fear now filled all Frodo's mind. He thought no longer of his sword. No cry came from him. He shut his eyes and clung to the horse's mane. The wind whistled in his ears, and the bells upon the harness rang wild and shrill. A breath of deadly cold pierced him like a spear...
The Witch-King disables Frodo and shatters his weapon quite easily with a single gesture.Flight to the Ford wrote:‘Then the leader, who was now half across the Ford, stood up menacing in his stirrups, and raised up his hand. Frodo was stricken dumb. He felt his tongue cleave to his mouth, and his heart labouring. His sword broke and fell out of his shaking hand. The elf-horse reared and snorted.’
The effects of what could have happened are exposed, and again we learn about how tough our little Hobbits are against 'magic'. This also reveals that there are other, lesser wraiths then the Nine, created by succumbing to the effects of the Morgul-blade.Many Meetings wrote: ‘“Elrond is a master of healing, but the weapons of our Enemy are deadly. To tell you the truth, I had very little hope; for I suspected that there was some fragment of the blade still in the closed wound. But it could not be found until last night. Then Elrond removed a splinter. It was deeply buried, and it was working inwards.”
Frodo shuddered, remembering the cruel knife with notched blade that had vanished in Strider’s hands. “Don’t be alarmed!” said Gandalf. “It is gone now. It has been melted. And it seemed that Hobbits fade very reluctantly. I have known strong warriors of the Big People who would quickly have been overcome by that splinter, which you bore for seventeen days.”
“What would they have done to me?” asked Frodo. “What were the Riders trying to do?”
“They tried to pierce your hear with a Morgul-knife which remains in the wound. If they had succeeded, you would have become like they are, only weaker and under their command. You would have become a wraith under the dominion of the Dark Lord…”
The idea of the Nazgûl being incorporeal is supported by their need to wear robes in order to affect the 'real' world.Many Meetings wrote:"I know," said Frodo. "They were terrible to behold! But why could we all see their horses?"
"Because they are real horses; just as the black robes are real robes that they wear to give shape to their nothingness when they have dealings with the living."
The Nazgûl ability to induce fear in others can be used on a larger scale, degrading morale and discipline.The Council of Elrond wrote:‘“Some said that it could not be seen, like a great black horseman, a dark shadow under the moon. Wherever he came a madness filled our foes, but fear fell on our boldest, so that horse and man gave way and fled. Only a remnant of our eastern force came back, destroying the last bridge that still stood amid the ruins of Osgiliath.”’
Clearly, brute force isn't enough to kill the Nazgûl; despite getting hit by a flash flood the best the good guys could hope for was that it would inconvenience them. Obviously as in this case if you destroy their garments they become powerless and must return to Sauron to take form again, but they will just keep coming back until you take out Sauron himself or have weapons specifically to sever that link (i.e. Blades of Westerness).The Ring Goes South wrote:"I am afraid it will wait," said Gandalf. "We can't start until we have found out about the Riders."
"I thought they were all destroyed in the flood," said Merry.
"You cannot destroy Ringwraiths like that," said Gandalf. "The power of their master is in them, and they stand or fall by him. We hope that they were all unhorsed and unmasked, and so made for a while less dangerous; but we must find out for certain."
Part of the search effort for the Ringwraiths involved sensing their presence, clearly a defined capability.The Ring Goes South wrote:'In no region had the messengers discovered any signs or tidings of the Riders or other servants of the Enemy. Even from the Eagles of the Misty Mountains they had learned no fresh news. Nothing had been seen or heard of Gollum; but the wild wolves were still gathering, and were hunting again far up the Great River. Three of the black horses had been found at once drowned in the flooded Ford. On the rocks of the rapids below it searchers discovered the bodies of five more, and also a long black cloak, slashed and tattered. Of the Black Riders no other trace was to be seen, and nowhere was their presence to be felt.
Even flying up in the air on their Fell Beasts, a Ringwraith's presence can still be sensed by others. It also survived the fall despite being shot out of the sky.The Great River wrote:'Frodo looked up at the Elf standing tall above him, as he gazed into the night, seeking a mark to shoot at. His head was dark, crowned with sharp white stars that glittered in the black pools of the sky behind. But now rising and sailing up from the South the great clouds advanced, sending out dark outriders into the starry fields. A sudden dread fell on the Company.
"Elbereth Gilthoniel!" sighed Legolas as he looked up. Even as he did so, a dark shape, like a cloud and yet not a cloud, for it moved far more swiftly, came ouf ot eh blackness of the South, and sped towards the Company, blotting out all light as it appraoched. Soon it appeared as a great winged creature, blacker than the pits in the night. Fierce voices rose up to greet it from across the water. Frodo felt a sudden chill running through him and clutching at his heart; there was a deadly cold, like the memory of an old wound, in his shoulder. He crouched down, as if to hide.
Suddenly the great bow of Lórien sang. Shrill went the arrow from the elven-string. Frodo looked up. Almost above him the winged shape swerved. There was a harsh croaking scream, as it fell out of the air, vanishing down into the gloom of the eastern shore.’
The Two Towers
Gandalf confirming that normal methods of damage-dealing aren't enough.The White Rider wrote:‘“The Winged Messenger!” cried Legolas. “I shot at him with the bow of Galadriel above Sarn Gebir, and I felled him from the sky. He filled us all with fear. What new terror is this?”
“One that you cannot slay with arrows,” said Gandalf. “You only slew his steed. It was a good deed; but the Rider was soon horsed again. For he was a Nazgûl, one of the Nine, who ride now upon winged steeds.”’
Quite clearly the Rohirrim felt the cold, fear-inspiring presence of the Nazgûl before actually seeing it.The Palantir wrote:'At that moment a shadow fell over them. The bright moonlight seemed to be suddenly cut off. Several of the Riders cried out, and crouched, holding their arms above their heads, as if to ward off a blow from above: a blind fear and a deadly cold fell on them. Cowering they looked up. A vast winged shape passed over the moon like a black cloud. It wheeled and went north, flying at a speed greater than any wind of Middle-earth. The stars fainted before it. It was gone.
They stood up, rigid as stones. Gandalf was gazing up, his arms out and downwards, stiff, his hands clenched.
"Nazgûl!" he cried.'
Same as above.The Passage of the Marshes wrote:'In the falling dusk they scrambled out of the pit and slowly threaded their way through the dead land. They had not gone far before they felt once more the fear that had fallen on them when the winged shape swept over the marshes. They halted, cowering on the evil-smelling ground; but they saw nothing in the gloomy evening sky above, and soon the menace passed, high overhead, going maybe on some swift errand from Barad-dur. After a while Gollum got up and crept forward again, muttering and shaking.
About an hour after midnight the fear fell on them a third time, but it now seemed more remote, as if it were passing far above the clouds, rushing with terrible speed into the West. Gollum, however, was helpless with terror, and was convinced that they were being hunted, that their approach was known.'
Return of the King
As Boromir described, the Ringwraiths conduct psychological warfare on the hapless Gondorians, probably a combination of their reputation and the supernatural fear they inspire.The Siege of Gondor wrote:'The next day came with a morning like a brown dusk, and the hearts of men, lifted for a while by the return of Faramir, sank low again. The winged Shadows were not seen again that day, yet ever and anon, high above the city, a faint cry would come, and many who heard it would stand stricken with a passing dread, while the less stout-hearted quailed and wept.'
Besides affecting the enemy's troops, the Witch-King can also "inspire" his own troops as well, even overriding their instincts for self-preservation.The Siege of Gondor wrote:'"They have paid dear for the crossing, but less dearly then we hoped...They swarmed across like beetles. But it is the Black Captain that defeats us. Few will stand and abide even the rumor of his coming. His own folk quail at him, and they would slay themselves at his bidding.'"
Luckily for Faramir it was not a Black Dart of the Nazgûl...The Siege of Gondor wrote:'"Faramir! Faramir!" men cried, weeping in the streets. But he did not answer, and they bore him up the winding road to the Citadel and his father. Even as the Nazgûl had swerved aside from the onset of the White Rider, there came flying a deadly dart, and Faramir, as he held at bay a mounted champion of Harad, had fallen to the earth.'
Whatever the Ringwraith use in their throwing darts is a potent poison.The House of Healing wrote:'"He is nearly spent," said Aragorn to Gandalf. "But this comes not from the wound. See! that is healing. Had he been smitten by some dart of the Nazgûl, as you thought, he would have died that night. This hurt was given by a Southron arrow."'
Even after being upgrade, Gandalf is still unsure about the outcome of a battle between himself and the Witch-King.The Siege of Gondor wrote:'"Yet now under the Lord of Barad-dûr the most fell of all his captains is already master of your outer walls," said Gandalf. "King of Angmar long ago, Sorcerer, Ringwraith, Lord of the Nazgûl, a spear of terror in the hand of Sauron, shadow of dispair."
"Then, Mithrandir, you had a foe to match you," said Denethor. "For myself, I have long known who is the chief captain of the hosts of the Dark Tower. Is this all that you have returned to say? Or can it be that you have withdrawn because you are overmatched?"
Pippin trembled, fearing that Gandalf would be stung to sudden wrath, but his fear was needless. "It might be so," Gandalf answered softly. "But our trial of strength is not yet come..."'
Not surprisingly, the power of the Nazgûl comes directly from Sauron, so if he pumps more power into them, they become more powerful.The Siege of Gondor wrote:'The Nazgûl came again, and as their Dark Lord now grew and put forth his strength, so their voices, which utter only his will and his malice, were filled with evil and horrow. Ever they circled above the City, like vultures that expect their fill of doomed men's flesh. Out of sight and shot they flew, and yet were ever present, and their deadly voices filled the air. More unbearable they became, not less, at each new cry. 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.'
Gandalf is able to provide relief from the effects of the Ringwraiths, if only temporarily.The Siege of Gondor wrote:'So it was that Gandalf took command of the defense of the City of Gondor. Wherever he came men's hearts lifted again, and the winged shadows passed from memory...And yet - when [Gandalf & co.] had gone, the shadows closed on men again, and their hearts went cold, and the valour of Gondor withered into ash...the faithful who remained at their posts were few, most had fled beyond the second gate.'
Witch-King is able to completely stop both sides from firing on each other or himself, and uses his magic in combination with the enchanted Grond to completely obliterate the massive steel doors of Minas Tirith.The Siege of Gondor wrote:'Over the hills of slain a hideous shape appeared: a horseman, tall, hooded, cloaked in black. Slowly, trampling the fallen, he rode forth, heeding no longer any dart. he halted and held up a long pale sword. And as he did so a great fear fell upon all, defender and foe alike; and the hands of men dropped to their sides, and no bows sang. For a moment all was still.
...
Then the Black Captain rose in his stirrups and cried aloud in a dreadful voice, speaking in some forgotten tongue words of power and terror to rend both heart and stone.
Thrice he cried. Thrice the ram boomed. And suddenly upon the last stroke the Gate of Gondor broke. As if stricken by some blasting spell it burst asunder: there was a flash of lightning and the doors tumbled in riven fragments to the ground.'
God damn that'd have been such a better scene then the one PJ gave us Anyways, making his sword burst into flame is a nifty ability.The Siege of Gondor wrote:'In rode the Lord of the Nazgûl. A great black shape against the fires beyond he loomed up, grown to a vast menace of despair. In rode the Lord of the Nazgûl, under the archway that no enemy had yet passed, and all fled before his face.
All save one. There waiting, silent and still in the space before the Gate, sat Gandalf upon Shadowfax: Shadowfax who alone among the free horses of the earth endured the terror, unmoving, steadfast as a graven image in Rath Dinen.
"You cannot enter here," said Gandalf, and the huge shadow halted. "Go back to the abyss prepared for you! Go back! Fall into the nothingness that awaits you and your Master. Go!"
The Black Rider flung back his hood and behold! he had a kingly crown. The red fires shown between it and the mantled shoulders vast and dark. From a mouth unseen came a deadly laughter.
"Old fool!" he said. "Old fool!" This is my hour. Do you not know Death when you see it? Die now and curse in vain!" And with that he lifted high his sword and flames ran down the blade.'
As we can see not everyone is affected by the Nazgûl's terror. Much of that has to do with working on people's fear of death, so for someone like Éowyn or Théoden who does not fear death and would willingly die, the terror is not as debilitating.The Battle of the Pelennor Fields wrote:'But lo! suddenly in the midst of the glory of the king his golden shield was dimmed. The new morning was blotted from the sky. Dark fell about him. Horses reared and screamed. Men cast from the saddle lay groveling on the ground. "To me! To me!" cried Théoden. Up Eorlingas! Fear no darkness!" But Snowmane wild with terror stood up on high, fighting with the air, and then with a great scream he crashed upon his side: a black dart had pierced him. The king fell beneath him.'
And so the Witch-King dies. The shrill cry is said to be heard all the way up to the Citadel, and afterwards a feeling of renewed hope is felt upon the defenders' hearts. Without his power the Nazgûl cannot challenge Gandalf (plus his death would hit morale hard) and so play a very diminished part in the rest of the battle, driving the army on from the rear.The Battle of the Pelennor Fields wrote:'Out of the wreck rose the Black Rider, tall and threatening, towering above her. With a cry of hatred that stung the very ears like venom he let fall his mace. Her shield was shivered in many pieces, and her arm was broken; she stumbled to her knees. He bent over her like a cloud, and his eyes glittered; he raised his mace to kill.
But suddenly he too stumbled forward with a cry of bitter pain, and his stroke went wide, driving into the ground. Merry's sword had stabbed him from behind, shearing through the black mantle, and passing up beneath the hauberk had pierced the sinew behind his mighty knee.
"Éowyn! Éowyn! cried Merry. Then tottering, struggling up, with her last strength she drove her sword between crown and mantle, as the great shoulders bowed before her. The sword broke sparkling into many shards. The crown rolled away with a clang. Éowyn fell froward upon her fallen foe. But lo! the mantle and hauberk were empty. Shapeless they lay now on the ground, torn and tumbled; and a cry went up into the shuddering air, and faded to a shrill wailing, passing with the wind, a voice bodiless and thin that died, and was swallowed up, and was never heard again in that age of the world.'
Obviously this quote has been argued over in the past, but it's quite clear from both earlier quotes about the Ringwraiths, and the observed abilities of the Blades of Westerness (i.e. fire-like glow, piercing Troll hide) that Merry's sword was specially made to disrupt the spells that sustain Nazgûl, which allowed the Witch-King to be killed by Eowyn permanently.The Battle of the Pelennor Fields wrote:'And still Meriadoc the hobbit stood there blinking through his tears, and no one spoke to him, indeed none seemed to heed him. He brushed away the tears, and stooped to pick up the green shield that Éowyn had given him, and he slung it on his back. Then he looked for his sword that he had let fall; for ever as he struck his blow his arm was numbed, and now he could only use his left hand. And behold! there lay his weapon, but the blade was smoking like a dry branch that has been thrust in a fire; and as he watched it, it writhed and withered and was consumed.
So passed the sword of the Barrow-downs, work of Westernesse. But glad would he have been to know its fate who wrought it slowly long ago in the North-kingdom when the Dúnedain were young, and chief among their foes was the dread realm of Angmar and its sorcerer king. No other blade, no though mightier hands had wielded it, would have dealt that foe a wound so bitter, cleaving the undead flesh, breaking the spell that knit his unseen sinews to his will.'
Obviously, surviving a fight against a Ringwraith can still lead to your death. The Nazgûl spent most of the battle flying high over the city, so this ability apparently has a very great range. Its absence from previous battles can be ascribed to the fact that Sauron was increasing their abilities for this fight.The Houses of Healing wrote:'But now their art and knowledge were baffled; for there were many sick of a malady that would not be healed; and they called in the Black Shadow, for it came from the Nazgûl. And those who were stricken with it fell slowly into an every deeper dream, and then passed to silence and a deadly cold, and so died.'
As above, killing the Witch-King can bring about the eventual demise of the attacker, a definite MAD situation.The Houses of Healing wrote:“…but the chief evil comes through the sword-arm. In that there now seems no life, although it is unbroken.
Alas! For she was pitted against a foe beyond the strength of her mind or body. And those who will take a weapon to such an enemy must be sterner than steel, if the very shock shall not destroy them.”
More psychological warfare.The Black Gate Opens wrote:'And from that evening onward the Nazgûl came and followed every move of the army. They still flew high and out of sight of all save Legolas, and yet their presence could be felt, as a deepening of shadow and a dimming of the sun; and though the Ringwraiths did not yet stoop low upon their foes and were silent, uttering no cry, the dread of them could not be shaken off.'
The Witch-King displaying some necromantic powers as it's revealed he's responsible for the Barrow-down Wights and other evil spirits haunting the land.Appendix A wrote:‘It was at this time that an end came of the Dúedain of Cardolan, and evil spirits out of Angmar and Rhudaur entered into the deserted mounds and dwelt there.’
Unfinished Tales
Their ability to inspire terror then is actually greater when not robed. This could explain why they aren't used in their invisible forms more often, besides lacking the ability to interact without clothes.The Hunt for the Ring wrote:'At length he resolved that no others would serve him in this case but his mightiest servants, the Ringwraiths, who had no will but his own, being each utterly subservient to the ring that had enslaved him, which Sauron held.
Now few could withstand even one of these fell creatures, and (as Sauron deemed) none could withstand them when gathered together under their terrible captain, the Lord of Morgul. Yet this weakness they had for Sauron's present purpose: so great was the terror that went with them (even invisible and unclad) that their coming forth might soon be perceived and their mission guessed by the Wise.'
The Nazgûl's lack of free will is explained, as well as additional weaknesses.The Hunt for the Ring wrote:'They were by far the most powerful of his servants, and the most suitable for such a mission, since they were entirely enslaved to their Nine Rings, which he now held himself; they were quite incapable of acting against his will, and if one of them, even the Witch-king their captain, had seized the One Ring, he would have brought it back to his Master. But they had disadvantages, until open war began (for which Sauron was not yet ready). All except the Witch-King were apt to stray when alone by daylight; and all, again save the Witch-king, feared water, and were unwilling, except in dire need, to enter it or cross streams unless dryshod by a bridge. Moreover, their chief weapon was terror. This was actually greater when they were unclad and invisible; and it was greater also when they were gathered together.'
The only other Ringwraith to be named by Tolkien, along with his own strength and weakness.The Hunt for the Ring wrote: 'Of Khamul it is said here that he was the most ready of all the Nazgul, after the Black Captain himself, to perceive the presence of the Ring, but also the one whose power was most confused and diminished by daylight.'
Confirmation of the Witch-King's necromatic powers, summoning the evil spirits that tormented the Hobbits during their journey through the Old Forest and Barrow-Downs.The Hunt for the Ring wrote:'In notes on the movements of the Black Riders at that time it is said that the Black Captain stayed [in the Barrow-downs] for some days, and the Barrow-wights were roused, and all things of evil spirit, hostile to Elves and Men, were on the watch with malice in the Old Forest and on the Barrow-downs.'