Aragorn's guess is that Sauron fears Isildur's heir and the sword of Elendil as powerful adversaries, knowing that he's reached a critical point in his plans:
Quote:
To know that I lived and walked the earth was a blow to his heart, I deem; for he knew it not till now... Sauron has not forgotten Isildur and the sword of Elendil. Now in the very hour of his great designs the heir of Isildur and the Sword are revealed; for I showed the blade re-forged to him. He is not so mighty that he is above fear; nay, doubt ever gnaws at him
The Passing of the Grey Company
|
I can't remember very much about the film universe, but if it does make the title a matter of fear rather than the man or the sword then it's a strange divergence from Tolkien, who places far more emphasis on personal worth than aristocratic rank. In the book, Sauron fears Aragorn, heir of Isildur, not the King of Gondor. Aragorn deliberately plays on this fear and doubt when he leads an army to the Morannon to draw Sauron's attention away from Frodo and Sam. The heir of Isildur is a likely candidate to take up the Ring against Sauron, and his leading a pitifully small army against Mordor is what Sauron would expect of a powerful leader falling under the Ring's domination.