Yule Mathoms 2005 Collected
December 16 - 9 nervous Nazgûl: 3. Worth the Risk - by Gwynnyd
Parts of Barad-dur stood, though Sauron no longer inhabited it. The Dark Lord gave them power, enslaved them, deserted them. He gathered them together in the chaos following Sauron's downfall, when they would have scattered, half of them wandering witless in the bright sunlight. Their rings - his ring was somewhere in the rubble of the tower. He lusted to wield it for his own purposes, and not feel Sauron's overriding will bending him. They were afraid still and would crawl if their master required it. But if he held his ring… he stilled his nerves, and drove them forward.
"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."
Unfinished Tales, Part 3, Ch 4, The Hunt for the Ring: Of the Journey of the Black Riders