Blackrat
He Who Lurks Beyond The Veil
Thinking forward the campaign, what do you think of converting Curse of Strahd to Faerun? Maybe set it in Westgate, which if I remember right is supposed to be plagued by a vampire. Rename Strahd to suit the area. See the background of the current adventure is that a powerful vampire sent his minion to steal a minor artefact, but the artefact possessed the minion vampire. So the master vampire could be (renamed) Strahd