However, this is often hard to pull this off in RPGs. In old-school games you could sometimes fake it by railroading the characters, but this was rarely satisfactory. In a narrative-heavy game, the GM has even less control over the story, and that can make fulfilling these promises even harder.
I've said it before, and I'll say it again. Consistency is hard. And, as gamers, we don't have the freedom to go back and edit things. We've got to get them right the first time.
So, instead of just hoping that everything will work out, let's create a framework to set and resolve these expectations.
Let's start with Rich's first law of gaming, every conflict should move the story forward. Generally speaking, the winner of a conflict gains some narrative control over the scene. They could use this to gain some clue, earn an ally, or otherwise throw a wrench into the opposition's plans. If they fail, things generally take a turn for the worst. But, most of the time, these are immediate effects.
But, do they need to be immediate effects? What happens if we let the winner establish an expectation related to the conflict. We record this expectation, perhaps on the character sheet or in the GM's notes, with the explicit promise that it will come to pass sometime in the future.
For example, our hero decides to seduce an opposing femme fatal NPC. If he succeeds, he sets the expectation that she will switch sides at some undeclared point in the future. We don't know when this will occur, but the expectation becomes part of the story. The GM may change her behavior to foreshadow this event. Then, at a dramatically appropriate moment, she betrays the other bad guys. Of course, she may just stab our hero in the back five minutes later, but at least we've fulfilled our initial expectation.
Of course, player's shouldn't get all the fun. For example, the same hero loses a dual against a minor opponent. The gm could set the expectation that one of the characters will kill the other, turning a throw-away villain into a major nemesis.
Or, lets turn this all on its head. I always like the idea of letting losers define the cost of their failure. Maybe the player decides he must kill or be killed by his opponent. Or the femme fatal decides that she's fated to change sides. Having the players self-select these expectation will help them buy into the story.
Long time readers might notice how well this fits into my Evolve or Resolve mechanic.
Remember, these are player expectations, not character expectations. The character may not know anything about them. He may believe the exact opposite, and may struggle against the expected fate. Rather, these are tools for the players. They are the load-carrying beams that connect past and future. They help give the story structure, while also giving the players more control over its shape.
I haven't thought this out completely. And it could probably use some play testing to flush out the details. What sort of expectation can we set? What are the limits? Which are better, specific expectations, or open-ended expectations? Can other players trigger an expectation's fulfillment? Should players be rewarded for playing into these expectations? Under what circumstances can we break these expectations?
I'd be interested in your thoughts here.