In my story, the main antagonist (there are four or five, two of those minor) is a German King who has come to Britain to invade. This sounds quite evil, but the reason is understandable: back in Germany, violent and severe floods were destroying his people's farms and they could no longer eat or live properly. So he set out to find the land other Germans had travelled to recently. He landed on the beach with his three sons and about fifty men (which was a medium-sized army in those days), and was met by a resistance, so he was forced to fight the locals. He then went around taking more land for his rapidly expanding people. I'm having trouble showing how he's really not a bad person since the POV characters are all Britons and they feel like he's stealing their land. And to be fair, he has killed a lot of Britons.