I'm basically just asking what "type" they are... you know... like the Volkihar and other ones.
Oh, well I think YOU can only transform into one. Other NPC's might have specific forms based on their stature. Though that in itself may raise some questions.
I know that Bethesda has been calling them vampire lords, if that is any help answering your questions, but I have no idea on anything more than that.
I know, but I mean... isn't their like a clan name for these Vampires? Maybe they're just the Ultimate Vampire with no specific name... who knows. I like the idea of these Creatures having a clan name for themselves.