[The Might]

Please don't think I'm absent from the thread, I keep thinking of possible answers but somehow none really fit the riddle
But I have another idea: Cirith Ungol

I'm as dark as night, - Cirith Ungol was a dark place
I run far from light, - and ran far from light
spell is upon me - or so it was said by Gondorians when talking about Shelob's presence
as you will now see. - as seen by Frodo and Sam
You'll beat me, I know - Frodo and Sam were able to pass
your friend is now lost, - Frodo was taken captive
but that was the cost. - for attempting to take that road