@deathmailrock Sorry, I don't really understand what you are saying. He was told he isn't needed anymore, that his contribution makes no difference anymore, and in fact he makes the army weaker by not being able to use magic. He was like a person fired from a factory because a product line was cancelled. How many millions of such people are there in the world? Most of them wouldn't be happy, but that's life. The very first chapter already made it clear he didn't question getting told to move on. He assumed it was for a valid reason. You may ask if it's fair to blame four people for causing trouble for the whole nation, but those four are among the highest authorities in the demon country, so, yeah, it's perfectly okay to blame them. If they are such idiots, it's also perfectly okay to blame those that put them in power (the previous heavenly kings).
@SunSun It doesn't matter. The current leadership is making the decisions. Three out of four heavenly kings wanted him gone, one didn't say anything, just let it happen. Maybe the other, non-heavenly king, leaders weren't even informed of the decision, but after all this time, how many of them have come looking for him?