Look, that stuff is obviously dark to you but not me. Maybe we have different definitions of dark here. But blood sucking vampires and sacrificing kittens is not dark in my book. That’s just murder and animal cruelty.
My kind of dark is like Eternal’s world, which I just recently read or an even better example is the prince of nothing trilogy. Dark, unforgiving, cruel and brutally realistic. This type of dark just doesn’t kill your family at the beginning like Unnatural, it lets you get to know them, get to love them as characters and then and only then do these characters die off in the most heart-wrenching way.
Other than that, I don’t really know how to explain it. We all have our own definitions of dark and that makes it hard to put to words.