It is an unique well thought through anime. It has quite unique characters with really good character development however still missing a few mysteries that they did not solve at the end. Also making the ending slightly disappointing. Despite this, everything that had happened in the anime made up for it completely.
The characters had voice actors that fit them, great music especially when Yato casts the 'spell'.
It is incredibly impressive despite the short 12 episodes. I think it needs a second season.
I definitely recommend it very much if you like anime that I like (take a look at my profile ;))
