OH MY GOD.
What can i say, this is one of those stories that has so much potential that go to waste.
I love and hate every thing about this manga, most of my hate can be turned to love if i watched the anime instead.

The translation that i read gave me a constant headache because of the accents, the action scenes were lacking, some were amazing but others you wont see anything happen and the worst of all is when there is a fighting scene and you have no idea wtf is going on, where is right where is left who is that and what is he even doing.

So like i said this is probably one of the few mangas that i recommend watching the anime instead.

But still it's a really good manga but would've loved to see more character development or more background, the characters are amazing but we need more info about them, something to sympathize with, also they develop way too fast that in some cases it doesn't even make sense.
some even feel like they are two different people and others you don't know what even happened to make them change like that.

anyway, it's a story about vampires, the Vatican and -you will find out when you read it-, so basically everything that you would ever need in a story.