Sauron and the Nazgûl

Sauron and the Nazgûl: the Dark Lord forged the Nine Rings to enslave mortal kings, binding their wills utterly to his own; the Ringwraiths became his most terrible servants, shadows under his great Shadow, their existence and power contingent on his.

The Forging of the Nine and the Enslavement of Mortal Kings

In the Second Age, Sauron the Great, the Dark Lord, gave Nine Rings of Power to proud and great Mortal Men, ensnaring them. Long ago they fell under the dominion of the One Ring, becoming Ringwraiths, shadows under his great Shadow, his most terrible servants. The Nine he gathered to himself, for he made that Ring himself, letting a great part of his own former power pass into it so that he could rule all the others. If he recovers the One, then he will command them all again, wherever they be, even the Three, and all that has been wrought with them will be laid bare.

The Nature of Their Bond: Will, Power, and Dependency

The Nazgûl are not independent beings; their power and even their physical form are contingent on Sauron. They cannot be destroyed like ordinary creatures. The power of their master is in them, and they stand or fall by him. When the Ringwraiths were unhorsed and unmasked at the Ford of Bruinen, they were made for a while less dangerous, but they were not destroyed. They are crippled without their horses, but the Ringwraiths themselves cannot be so easily destroyed. Their existence is a state of being half in the wraith-world, and they are bound to the will of the Dark Lord. The Ring itself draws them, and they feel the presence of the Ring-bearer more keenly than any other sense.

The Witch-king as Chief Captain

The Lord of the Nazgûl, the Witch-king of Angmar, is the chief of the Nine. He is a great king and sorcerer of old, wielding a deadly fear. He is the Morgul-lord, the Black Captain, a spear of terror in the hand of Sauron, a shadow of despair. He leads the Nine in their fell deeds, and his will is the direct instrument of Sauron's malice. The other Ringwraiths are utterly subordinate to him, acting as his lieutenants and executing his commands. The Witch-king's own power is immense, but it is ultimately derived from and subservient to Sauron's.

The Ringwraiths as Instruments of Sauron's Will

The Nazgûl are the primary agents of Sauron's will in the physical world. They are sent to hunt the Ring, to spread terror, and to command his armies. They are the most feared of all his servants, and their presence alone can cause despair and madness. They are not merely warriors but also spies and messengers, able to see and hear things that are hidden from others. Their power is in terror, and they are strongest in dark and lonely places. They will not openly attack a house where there are lights and many people, not until they are desperate. Their senses are not limited to sight and smell; they can feel the presence of the Ring and those who bear it, and they can perceive many signs and forms that are hidden from mortal eyes in the dark.

The Limits of Their Power and Their Ultimate Fate

Despite their terrible power, the Nazgûl are not invincible. They can be resisted by those with strong wills, and they are vulnerable to certain powers, such as the light of Elbereth and the fire of Gandalf. They are also bound by the will of Sauron and cannot act independently. Their ultimate fate is tied to the fate of the One Ring. When the Ring is destroyed, the power that sustains them is broken, and they are utterly annihilated. The Nazgûl, caught in the fiery ruin of Mount Doom, crackle, wither, and go out, their existence ended with their master's fall.