Aragorn är Isildurs arving
Som den rättfärdiga kungen till Gondorens troner 1 (och Arnor återupprättades) hade han möjligheten att återförena den dunnade kungaden i Dúnedainen: Arnor och Gondor, för att motsätta sig Sauron.
Then Aragorn, being now the Heir of Isildur, was taken with his mother to dwell in the house of Elrond; and Elrond took the place of his father and came to love him as a son of his own. But he was called Estel, that is "Hope", and his true name and lineage were kept secret at the bidding of Elrond; for the Wise then knew that the Enemy was seeking to discover the Heir of Isildur, if any remained upon earth.
Den större orsaken till att Sauron var så rädd var att:
Sauron (felaktigt) trodde att Aragorn hade ringen och skulle använda den mot honom
'Now Sauron knows all this, and he knows that this precious thing which he lost has been found again; but he does not yet know where it is, or so we hope. And therefore he is now in great doubt. For if we have found this thing, there are some among us with strength enough to wield it. That too he knows. For do I not guess rightly, Aragorn, that you have shown yourself to him in the Stone of Orthanc?'
'I did so ere I rode from the Hornburg,' answered Aragorn. 'I deemed that the time was ripe, and that the Stone had come to me for just such a purpose. It was then ten days since the Ring-bearer went east from Rauros, and the Eye of Sauron, I thought, should be drawn out from his own land. Too seldom has he been challenged since he returned to his Tower. Though if I had foreseen how swift would be his onset in answer, maybe I should not have dared to show myself. Bare time was given me to come to your aid.'
Därför hade Sauron allt mer anledning att frukta Aragorns makt. Även om han var en dödlig man, slog Aragorn "Orthanc-Stone mot" Saurons vilja . Det är definitivt att vara rädd för Aragorn.
Jag tror inte att Aragorn hade en mycket liten mängd av Maiar-blod i honom var anledningen till att Sauron fruktade honom, som många av de andra svaren som antagits tycks föreslå. När Aragorn föddes var hans Maiar-blod så utspänt att det kan anses vara irrelevant. I detta utmärkta svar Aragorns Maiar blodprocent beräknas vara 0.000000000000000001355%
.
1 : Detta är perfekt svarat här .