Who Really Killed the Witch King in ROTK??

[Noble Elf Lord]

Originally Posted by Gordis

Fading is the biggest Elven problem there is, much like early death is for Men.

In the original design of Eru all Arda was supposed to be much like Valinor, suitable for Elves, where they could live happily till the End of Time. But Arda had been marred by Melkor, which broke the design of Elvish immortality: in Arda marred, Elves slowly and inevitably fade, their bodies gradually becoming invisible.
First they appear like sad shadows of their former self, until at last they are naught but wraiths (much like the nazgul, in fact, but not evil). Only in Valinor can Elven fading be delayed, which is one reason all Elves have no choice but to go to Valinor in the end.
One of the special abilities of the Elven Rings of Power was that they could delay time, and as such were used to prevent fading in Rivendell and Lorien. After the destruction of the One ring the ancient Elves had no possibility to stay in ME, so in the FA the Eldar left for Valinor.

Thank you, my favorite Nazgûl! Then again, this makes me wonder when I'll start to fade, or if it has already began. ...... well, I can still see myself and such....