I honestly don't get why are people complaining on this manga, particularly because it didn't end up as a teenage shoujo vampire-loves-hapless-girl? Um, hello, not all mangas have to end up as clichés, which is GOOD, to most of us jaded readers out there.
Personally, this is one of the best vampire mangas I've read around, even more so than Vampire Knight. It has everything, mystery, intrigue, horror and a little bit of psychological thinking as well. If that's not your cup of tea, then stay away from this one.
It has fairly mature themes as well, so if things like 'rape', senseless killing, and all that stuff isn't something you can stomach, then don't even read it.
My only complaint, as others have pointed out already, is that the ending seems too 'loose'. The manga-ka could have done a better job in explaining more about this whole 'life, death and revenge' business, instead of shoving in a chapter that barely ties the loose ends and has more open-ended holes instead.
Still, the sum is more than the total of its parts, so I have to say, despite the lousy ending (the lack of explanation for all that mysterious, intriguing 'past' ) , it still makes up for it and this manga is one of the better, gothic vampire stories I've read for a long time. 😉
And yeah, I agree with destati, maybe the whole universe--or Kanna and Ren's universe, is inside that kid's toy.