Goddess

Queen Lana'thel. She's a blood elf. And a queen. And a vampire. Sorry, vampyr.

Have you seen her abilities? Vampiric bite, essence of the vampyr queen, shroud of sorrow. You might as well add "immune to shadow priests", we're all going to be too busy gasping in awe and reverence.

Do you think it's possible to defect to the Scourge? Does Arthas accept living recruits?