1.) Buck does mention the word God in a sentence near the beginning but not in a negative way. 2.) The Covenant can sometimes be heard calling the Master Chief a "Demon", but that is due to him standing in the way of their whole religious deal with lighting the rings and whatnot. 3.) *Kind of a Spoiler, not really though* [spoiler]Cortana is shown in a cutscene near the end and actually doesn't appear as nude has she has in previous games. However, if it still does not appeal to you then the cutscene can be skipped.[/spoiler]