Talk:Kenkou Cross Q&A/@comment-213.119.32.191-20141029200128/@comment-25035274-20141029204509

It's actually answered in one of the books. The reason the Demon Lord's armies haven't swarmed the planet (according to the in-world author) is because they're too busy enjoying themselves. In point of fact, the only reason they even attacked Lescatie in the way they did in the first place is because Lescatie had become exceptionally violent towards monsters.

In other words, the Demon Lord, et. al., would be happy to let things go as they are now, with them having their territory and the humans having theirs, except humans keep on with the stabbing and killing and murdering. At least, that's how I interpret it.