Gulavhar, the Terror of Arnor (and other assorted beasties?)

[Pitchwife]

a being from an earlier time that should have perished long ago - a winged demon with a hunger for blood.

Sounds like one of Thuringwethil's lesser relatives (vampires). Some of them may well have survived into the Third Age, just like the Balrog of Moria and Shelob ("the last child of Ungolianth") did.
My main problem with Gulavhar is that the name doesn't seem to make any sense. Is that supposed to be Sindarin, or what? If yes, meaning what? (Sorry, but I'm a philologist at heart, if not by profession.) Nothing against expanding on Tolkien's work, but can't we try to get the details right? But that's probably too much to ask from a merchandising company...