@larcek: Well, I imagine the whole world situation very advantageous and profitable for those in charge of the empire, even though their world gets invaded. They send their own dumb grunts and criminals into death (but not too much), while they demand stuff to fuel their own military power from other countries, who happens to have to shut the f*ck up. Of course the use those resources not only on their military, but also on the economy (actually a good thing in war, but also for afterwards (not that they want a afterward, as that war is too profitable)) and their own personal gains (embezzlement). And who should challenge them? They are the strongest and "justice". If you turn against them, they
have to fight you, as you pose danger to the survival of mankind (and those other people, too).
Oh, but MC's country isn't part of the alliance (if memory serves me right). An unallied country that stands strong and even grows its economic and military strength. They have to find a way to stomp out that danger to their nice way of life. There will be war. And this time it has a solid reason backing it.
It's kinda funny how it looks to be quite similar to our situation of global warming and countries/mega-concerns trying to use it to there advantage. Who's the one who has to cut one's economy/economic growth the least and survives as the top dog in the aftermath. Sometimes it really looks this way. The world "ending" and those fuckers, who celebrate it.
Back on the topic: So that's the difference between poisonous and venomous! The more you know.
Also I don't believe that war arc to be too long. It seems to be just right. Lucky me, it fits my taste. But I'm also here for the kingdom building and not some interpersonal shit of aristocrats, so on with the growth of the state!