Gothmog and the Mouth

[Ghazi]

Originally Posted by Inziladun

Granted, Eärnur's ultimate end was unknown, since there were no witnesses to his death, but I don't see what mechanism Sauron would have (other than the Nine) of prolonging his life for so long.
And how would he have 'turned' someone like Eärnur to his service, again without making him a wraith through use of the Nine?

Sauron was a necromancer and it is clear that the Lord of the Nazgul had some ability to extend the lives of the Barrow Wights, which I assume are the disembodied spirits of the Children of Iluvatar.