Crimson should verify, since it was his question, but assuming I'm right:
A dreaded and ancient tool am I
my visage the symbol of a dark knight
I drink the blood of those that I touch
though dreaded in whispered tones, I can't be found in Vvardenfell
the gods in their wisdom excluded me from their final vision of this land
What am I?
Crimson said " When you figure it out, there will be no doubt that it is the correct answer." I assumed that was the statement there is no need for clarification.
I know the Vampiric Ring satisfies at least three of those statements (dreaded and ancient tool, drink the blood, not on Vvardenfell) so that is my guess.