I've decided that this hero should be a jack of all traits! A sorceress who can change into a bat or summon a hoard of bats and is a swordswoman.
I voted for the concept of a Sorceress, and I think it would be the wisest solution
It could be interesting finding a kind of compromise among those three concepts (Vampire, Sorceress and Swordswoman), also because the results of the poll are quite even.
But, as I have already written in my previous comments, I don't really like the idea of a shape shifting Vampire in the Third Age, as it would be, I think, quite anachronistic and not lore accurate, being it a strong and deep reference to the First Age, that rightly and legitimately belongs only to Gorthaur in the Edain Mod.
That's why, I think, you should focus more on Sorcery or Black Magic, something that Angmar was very famous and feared about.
It's not a coincidence that the Ruler of this Realm is known as the 'Witch-king'.