Look, while there were a variety of different different things stemming off the idea of a force that drains your life force, only one of them is actually considered a vampire in modern times. It's possible that they used to lump them together in olden times, but eventually the myths managed to differentiate between the different forces that would drain you. Over time, myths over vampires would become more and more accurate, as more distinctions are formed between them and any other human feasting force of the night. Yes, I believe that there might be any number of other explanations for the vampire codex. I just described a general outline based off of what I thought was the coolest way they could be portrayed. It's quite possible as I made it sound like it was unlikely that there were other ways for them to be portrayed; I described what I thought was the most likely view, which was intended to make it sound more likely than other forms of vampires. However, I admit that there could be any number of ways to portray the vampires, and I admit my view could be very, very wrong indeed.
Meh. Maybe it's too complex, maybe not. Maybe vampires will just not come into the story at all. I just posted my view on vampires in a way that I thought they might be considered entertaining. A well-placed page or two (Yes, I know it's an ad, but it demonstrates my point) might be enough to show a little bit of the intrigue of the vampire courts, and leave the readers interested, but not actually describe all aspects of it in a full-blown exposition.