I like to think the predators are just predators in all their greatness, and the space jockeys are these great intergalactic beings that roam the universe for things, [Neither ever came into contact with the other]. They live to oversee life in its many forms, almost as if they were gods. And one day the aliens were discovered, being the most powerful evil force in the universe they ultimately brought about the demise of the Jockeys. The Predators in my eyes represent what humans are to god and the devil on that epic scale of events. The predators face great challenges because of the nature of the jockeys and the evil that is represented by the aliens. This is how I see the events of this Universe.