One of the best anime created, and the best on what I've watched!
The dark and gothic art & op/ending songs perfectly suits the anime's personality! The background sound effects is also amazing. Unique story. I love the thrilling sensation I felt on every episode. The kind of anime you want to watch in just one day, but because that's impossible you can't get it out of your mind and you'll wish that yesterday will come fast so that you can watch the next episodes. I love the lesson it portrayed, "don't try to be a god, because you're not and will never be."
I'll rate it 11/10!