The wars had been going on for years actually, but they weren't on the scale some thought they were. In a sense, they were small engagements here and there as the Darkness slowly creeped its way towards the borders of the human kingdoms. If only it didn't come.
For a while, there was a lasting peace that had ensued from years of war that left the different kingdoms weak and near collapse. And during that time everything seemed to 'click'. The other nations got along well with each other and humanity prospered and grew. It was paradise, put not anymore, it was quickly turning into anything but.
For a brief geography lesson there were three 'main' kingdoms, and about 5 smaller ones. These kingdoms slowly grew into interdependancy, which isn't a bad thing necessarily, but when one kingdom comes under attack and they have some necessary product that other countries need, you probably have figured out the rest.
Thus it has come that everyone has lost their own little slice of paradise. But some are willing to do anything to get it back. Anything.