I haven't fully fleshed out this idea yet, but here's what I'm thinking. You come across the devil and he offers you something really good. It could be (randomly chosen each encounter) a large amount of rupees, a bunch good items, a big increase to your speed, or whatever else we can think of here. In exchange you will die in X turns, randomly chosen from part of some range (not sure how many). This deal counts as a negative effect on you, but it cannot be removed in ANY way that you would normally dispell effects. If you're dead when your time is supposed to come then you die again as soon as you revive next turn.

If you refuse the devil's deal then you get nothing and nothing bad happens to you.

Hmm, well I don't think that they could recode the death sequence just for this event. That's why the punishment is an unavoidable death. If you get something like AIDS, you can use the condom or kill yourself to remove it early and don't worry about randomnly dying a few turns later. With this, you never know if something in the game might happen that you need to respond to (like using items on an opponent who's in the lead) that you won't be able to do because you'll be dead on the next turn. That's why it's a risk that he tries to tempt you to take.

I'm not sure if I like the repeated use of the event on multiple players, but it would be cool if when players refused the deal, he kept going around to other players until someone eventually accepts.

A deal with the devil event is something we've got planned. We haven't fleshed out the details, so it's good to see this discussion going on. I've seen some interesting ideas in this thread. I like the idea of players being able to choose how a player who's in hell will be tortured. Sounds fun.

If a priest makes a deal with the devil, does he become pope?