Funny to think that the main villain is also the hero of the story. This is not spoiler if you watched both the series and understand the movie. In my opinion, he could have have conquered the city on it's own. Control the King and let them rule them selves. No need to do the mirage Invading Army and faking the death. He could have taken more loyal humans with him if he have done it in my opinion but a good movie none the less.