Not a good main character that I had hoped for. Ava is selfish, irrresponsible, always says I don't want to be warrior, but does not return Halo, even when she knows that it is critical for fight against demons. She doesn't care about anyone accept having relation with boyfriend to whom she continuously lies. Even when Lilith sacrificing herself to save Ava, she is stubborn and feels it was Lilith's fault that she was after Ava to take out the Halo. Many weak points in storyline and one-dimensional characters.