Well i have not beaten the game, heck i don't even have an xbox but i have played it, read the books, read countless forums, and beat halo 1, so what i think that will happen is that at first the human and the elites will have an uneasy truce, they will fight to destroy or atleast make a peace treaty with the covenant. I really don't know much of what can happen after that cause i have not beaten the game, but i am gonnna get an xbox soon, and this is gonna be th efirst game i get!