My fellow GM's, I need advice. I'll start from the beginning: Other than a few 1v1 practice tries that quickly fell apart for lack of players, I'm a noob GM and will be GM'ing my first true campaign with more than one player(all noobs) this week. I'm fairly confident I have my stuff together from observing other GMs, but there is one player I can see trouble coming from and I want to be able to head it off before it can become a problem. One of my players is having trouble understanding his motivation if you will. First, he expressed interest in overthrowing the God-Emperor of Mankind. I explained to him that: 1) attempting to kill the Messiah would be a bad idea, 2) He would never get past the Custodes, 3) the Calixis Setting is nowhere near Terra, and 4) that in any event, The Emperor has been in a catatonic state, and that the Imperium is run by the High Lords of Terra.(Perhaps I should have called them by their alternative name, instead.) Now he wants to overthrow the High Lords of Terra.
I explained to him that yes, the Imperium is the worst form of government, that it combines the worst elements of Feudalism, Absolute Monarchy, Nazism, and Communism, but that it is the only thing that stands between Humanity and extinction. He tells me, "then it is better for humanity to die out then turn evil." I'm a friend of players of a radical bent, but even Istvaanians want the Imperium to prosper. I have a free-wheeling philosophy, but this would be a game breaker. The game mechanics don't even make it possible to play a heretic, How would that even play out: "player: I swear eternal warfare against the Imperium. GM: you role a 100 corruption points, you're character is now an npc villain. Player 2: I attack him. Player 3: Ditto. GM: your fellow players turn you former character into chunky salsa. Would you like to write up another character."
Finally, I made it clear in no uncertain terms that even expressing seditious thoughts IN-CHARACTER was a suicidal action that would likely get him declared excommunicate traitoris. He seemed to back down from his crunchy quest to destroy the Imperium after that. But if I know my brother, he will simply act more covertly to subvert the game. I can always use a bolt of lightning on a clear day, but I don't want to use that except as a last resort. How do I keep the game from being totally derailed in the first place? WHAT SHOULD I DO?