Characters are relatively simple, never reaching incredible levels of depth are written with an air of believability and feel real. Each member of the main cast is solid. Teru is a great stand in for the reader, asking the same questions any person would be placed while in his situation and the relationship he builds with Ako makes the hellish environment they are thrown into just barely a degree safer.
From that I'm lead into the general story and the presentation of the mystery: very good. The mysterious disaster that occurs at the very beginning isn't terribly shocking and isn't a twist when you actually figure it out but it's satisfying nonetheless. The side effects of such a monstrous disaster is really the main draw of this story and are executed/presented beautifully. Tying in directly to the art it's probably what does a lot of the heavy lifting of this manga (not to say that it's not great or poorly written, just that it's probably it's strongest suit.)
The art ranges from solid, to utterly haunting. Japan is turned from what was once a beautiful country to visions of hell. Sweeping landscapes of absolute destruction, pits of pure darkness, and waves of death plague the once stunning country and really sell the mystery and horror caused by the mysterious disaster.
The ending sequence is probably the only really weak part of the whole story as it introduces a regardably important group that doesn't get enough build up or screen time before the story ends, but that's really the only major flaw. The ending in and of itself is incredibly strong, displaying an overwhelming feeling of utter hopeless despair; but is juxtaposed with an absolute almost foolish degree of hope for the future.
All in all I had an incredible time with this manga. Well written, gripping, and a great time. Highly recommended.
