Stranded in the space between human and demon, Miyu was born a vampire and charged with the responsibility of returning evil demons called Shinma to the dark. Being eternally 15, she yearns to return to the dark herself but not until she has banished the Shinma from Earth. And since her awakening, she remains cut off by the facts of who and what she is.

Subtle. In a word. This is an original anime, not because of its concept, but because of the way it affects without you even noticing. If you are not carefully paying attention you might have to watch the entire thing over again to find out where the story starts and where the beginning truly is.
I am not saying this anime doesn't have its faults. It definitely does. The whole kill a monster every episode thing is incredibly obvious and borders on insulting the audiance.
Somehow it manages to save itself from the drugery that single problem brings up with consentrating really hard on the enemy's past and reasoning. The torture that the human souls go through can be heartwrenching, but their release does come to one degree or another.