immortality

[Westerly Wizard]

From the essential nature of orcs, as the antithesis of elves, it should be apparent that orcs are not immortal. The origins of orcs is margin gloss to the whole discussion.

Bill Ferny, whether that idea provides the right answer or not, dismissing the origin of orcs due to there nature as the antithesis of elves is a great oversimplification. When the orcs were, in Tolkien's mind, corrupted elves, they would only be able to become mortal at Eru's bidding, because he was the only authority who could change the nature of the Children. Thus, Melkor's intention of making them the opposite of elves cold not effect orcs being mortal because only Eru could do this.