Rin Okumura, our main Protagonist, lives a fairly normal life until the day he finds out he is the son of a demon - more specifically: the living offspring of Satan. Quite a promising premise for a shounen anime; unfortunately, it could not keep its promise, mainly due to its characters and storyline.
Having said that, this leads us to the first issue: the Story. Ao no Exorcist starts off strong; throwing both you and Rin into unfamiliar territory filled with demons and priests and a very interesting actual state of the world and how it is divided. But soon after, the story develops into a veritable donwfall. The Serie suffers greatly under its predictable storyline and lacks of the much needed depth which is essential to keep the story interesting for the rest of the show. Rather than giving us a better picture of the two worlds, the Story is filled with bland humour and uninteresting storyarcs instead.
Ao no Exorcist revolves around two worlds; the human world "Assiah" and the demon world "Gehenna". One does not simply travel between these two worlds unless you have a key which, paradoxically, quite a bunch of poeple seem to have. With this being the case it appears as if this key had been sort of a giveaway long time ago.
Let us have a look at the characters of Ao no Exorcist. Rin Okumura appears as the stereotypical shounen main protagonist; not much intelligence, edgy personalty,... . He might be likeable, but is definitely not worth being called memorable.
Yukio, his brother, serves as the smart, clever boy who tries to hold his brother in check throughout the anime - but offers not very much to the story itself.
And of course there is a archetypical girl in the anime which, after all, can easily be compared to Sakura from Naruto or Asuna from Sword Art Online. They all share and possess the same stunning quality to serve a story.
However, there were things that deserve a certain amount of praise. Let us begin with the Animation and the visual quality. The regular animation (CGI has been used as well) and the visuals of the demons did not disappoint. The variety of demons that were presented can arguably be
classified in "exceptionally creepy", "fancy little badass" or "cute little fellows".
Editing/Cutting were well-directed and the Music/Sound were appropriate for each scene. That is all we can ask for.
In conclusion, the anime does not have the dark tone as we could have expected out of the first few episodes. Surprisingly, however, it possess a reasonable amount of Entertainment, especially at the beginning. Therefore, Ao no Exorcist cannot be classified as entirely bad rather than wasted potential.