[Gil-Galad]

well i thought it was obvious at how the nazgul could relate and it did not need explaining, but if you need it legate then i guess i have too

I'm as dark as night, - nazgul is dark
I run far from light, - nazgul is scared by gandalfs light of istari
spell is upon me - bound by the ring
as you will now see. - they serve sauron, all see it
You'll beat me, I know - they get killed but coem back
but I bring the woe: - they hunt down anyone in their way
your friend is now lost, - use to be kings of men
but that was the cost. - cost of losing their soul


now for my second guess, i'm going with Sauron

I'm as dark as night, - Sauron has always been referred to as dark
I run far from light, - escaped when Valar came
spell is upon me - bound by the one rin
as you will now see. - his spirit( great eye) lingers
You'll beat me, I know - lidless eye sees all?
but I bring the woe: - causes greif to other "good" kingdoms
your friend is now lost, - was once a maiar of Aule
but that was the cost. - left his past life to join Melkor