I don't know how to feel about this manga. It's a weird mix of fantasy sci-fi, they need to do a good job in explaining how this all works. And there doesn't seem to be much tension ever in this manga because they always miraculously find some super convenient item or thing that helps them through without much personal ingenuity and thinking. The only real driving force behind this manga is wondering what that corrosion rate thing is and the bigger picture behind all of it.