Story (7/10):
The story is original, I'll give it that. It was different than lots of other things I've seen, but similarly enough that it wasn't absurdly unrealistic. The one thing however, is that no one ever actually gets to their real goal.
The anime shows in the first few episodes that everyone is clearly guided to defeat the Demon God, but they all hit a detour when they get trapped inside the barrier. As the show goes on, it takes the entire first season (hoping there'll be a second) to get out of the barrier and reveal the Seventh.
My only real problem with the story, is that they get too off topic from it. I originally thought it would be a story about trying to defeat the Demon God, but instead I got surprised with a completely new story.
Additionally, the anime can go really slow. Even though it's only 12 episodes, the creators could've spent less time in the beginning doing pointless things and spent more time showing hints towards the Seventh.
Art (9/10):
No complaints about the art, I think it is phenomenal. All the characters have their own distinctive physical looks, which I really enjoyed.
The backgrounds are amazing too, although a lot of it goes to waste as you spent from episode 4 and on staring at scenery of fog and trees.
Sound (8/10):
The sound was great. The background music was all perfectly in place and added a lot of suspense.
The OP's were good. The first one was mediocre, but the second one exceeded so far beyond my expectations.
Chracter (7/10):
My main problems would probably be the characters. None of the characters except Flamie and Adlet got any time dedicated to their past. The creators spent too much time showing Flamie's trust issues and Adlet's cockiness that no one else got any screen time.
That being said, the pasts that they showed made me dislike Flamie even more than I first did. She was a stubborn, emotionless person, but it felt like it was so over exaggerated that it got to the point where it was unrealistic.
Enjoyment (9/10):
As far as my enjoyment goes, I really had a great time watching this anime. It made me want to know what happen and develop having theories of my own.
Overall (8/10):
Honestly, this anime was amazing. It is beyond words, especially if you love mysteries. This anime had me suspecting almost everyone at some point, even the main protagonist.
My only regret is: now I have to wait for the second season
