Okay, so, here's the thing. In my fantasy novel, there are many kingdoms warring with each other, courtesy of many gods playing around with fate and what not, akin to the Illiad. These gods are the true villains of my story. Now, I want to write an emperor/king who just so happens to be on the opposing side of the main character's conflict. In other words, a villain only by circumstance. How do I go about writing such a character, who shares many ideals with the main protagonist, yet is fated by the gods to confront him?