Sorry for taking so long, I hope you like the ending :)
He was right. Sauron's Orcs knew his name, and Sauron remembered him. As - guarded by Nazgûl, no less - he ascended the tower of Barad Dûr, he felt almost physically sick. The Silmaril was closer than it had been since before he swore the Oath. The Oath. It screamed at him, tugged at him, urged him ceaselessly to run up the stairs two at a time, leap on Sauron and take his rightful property. And Fëanor wanted to do that. He wanted to do that so much that he could hardly tell the difference between what he wanted, and what the Oath wanted.
But Dûrfîn did not want that. Dûrfîn wanted to live, he wanted to do what he wanted to do, not what destiny and higher powers ordered. And that meant going back, back to when his greatest worry had been displacement as smith by a Dwarf. Dûrfîn had been almost asleep when Fëanor leapt into his suicide attempt to get his Silmaril back. Now Dûrfîn was awake, wide awake, but he was having a great deal of difficulty curbing his Fëanor desire to leap and run and reclaim his own, if only for a few seconds before death overtook him.
The last stairs. He ascended them, turned a corner, and the door was opened. And there, in a room walled with glass, stood Sauron, not looking in the least like he had appeared the last time the Elf had seen him. But as that had been in the First Age, thousands of years ago, it was hardly surprising. Sauron looked like an Elf, dark and he might have been fair, but Evil twisted his face. And upon his right hand lay a golden ring. And set in the ring blazed a stone of white fire. Fëanor's Silmaril.
Sauron smiled, and nodded his head. "I wondered if you still lived. Can you remember your own name, these days?"
"You have my Silmaril." Fëanor said.
"You have incredible powers of deduction!" Sauron said, and then waved a hand at his Nazgûl. "You may leave us. Go, aid your lord."
The Nazgûl hissed in answer, turned, and walked back down the stairs. Sauron held out his hand to the Elf. "Go on. Try and take it. It will burn you, Fëanor. You are a creature of Evil, as am I. Remember the kinslaying at Alqualondë? Remember the burning at Losgar? Do you want to know how many died by your hand?"
He could not feel guilt for those things. Fëanor felt no guilt. The Teleri had deliberately obstructed him, his brother had plotted to murder him! It had been only Fingolfin's fault that his followers perished in the Helcaraxë! Dûrfîn felt the anger of his memories, but he could feel no guilt. Fëanor, not Dûrfîn had done those things.
Dûrfîn smiled, his twisted, scarred face breaking the expression into a ghastly thing. "This hand, indeed, is Fëanor's," He held out his unblemished hand. "But this is Dûrfîn's. And Dûrfîn did not do those things."
With his knotted, stiff hand, he reached out and grasped the Silmaril. And he felt no pain.
Sauron let out a bestial howl and pulled back. At its master's command, the Silmaril began to burn him, his finger began to swell and change colour, and wrinkles appeared on his face. He leapt back, and snatched a blade from the wall into his hand. "Die!" He shouted, and thrust the sword towards Dûrfîn.
The Elf twisted aside, but only just. His eyes grazed the walls frantically, but there was no sign of a weapon. He leapt back from the advancing Dark Lord, and sent a call to the Silmaril, urging it to hurt Sauron, to withdraw its power from him, to burn him. Sauron cried out as his whole hand began to turn red, and he lunged once again at his enemy.
The Elf let out a cry of pain as Sauron struck his arm, only a glancing blow, but the Maia's great strength cut deep into his flesh and grazed the bone. Memories of an ancient battle with Gothmog danced before his eyes, and he knew with an awful certainty that there were only two outcomes to this - it could hardly be called a battle - confrontation. Either he died - or he died and took Sauron with him, separating him from his body and forcing him to grow another. There was no choice.
Together, Fëanor and Dûrfîn leapt towards Sauron, knocking him backwards. The Dark Lord let out a cry of shock, before he and his Elven assailant crashed into the glass wall and shattered it. Together they fell, a stream of glass tumbling around them. Sauron's sword was whipped from his grasp by an onrush of wind, and then they struck the ground. Discontinuity.
Frodo Baggins, stumbling across the plains or Gorgoroth, gave a sudden gasp. When Sam hurried to ask what was wrong, Frodo said "Something's happened, Sam! The Ring - it's as light as a feather!"
The guard at the gates of Mandos was most confused when two fëar from the same hröa turned up, asking for entrance. She had to ask for advice from Námo himself. The Lord of Mandos came to the gate and said "Let them both in. They are here under rather - special circumstances."
Dûrfîn asked him "Did we kill Sauron?"
Námo shook his head. "No, you killed his body. Frodo Baggins is the one who will kill his strength, and leave him with nothing but his malice."
