
Valandil Ancalime |

My pc's released a Pit Fiend, who owes them a favor. Later 1 of them, a worshipper of Desna, dies (while the rest are captured by demon worshippers and in dire straits). While the dead soul is waiting around Pharasma's Boneyard, the Pit Fiend arrives and offers him a deal. "I can raise you, for a price..."
I need a subtle price. No soul selling, no first born, nothing obviously evil. The player is really smart, so it has to be something really subtle.

chaoseffect |

"Take this package to X on the Y day of Z saying it's from W."
It appears to be a completely harmless item and by all accounts would be if not for the fact that it is easily identifiable and used to belong to a man who disappeared and was thought murdered. PCs are delivering it to the family and by all means appear as though they're working for the murderer, W, the head of a rival family to the murdered man's. Whether or not W was involved is besides the point. Bonus points if you make the families nobles and can break the kingdom's uneasy peace and throw the place back into civil war.
...that's all I got off the top of my head.

Infernal Contract Broker |

Well if you want my professional advice you have them pay you back with one day of service. When they ask why the service is so light point out the whole point of them helping him earlier.
The service? Charity work in Lord Asmodeus name. Nothing outrageous, feeding the poor, clothing the beggars, helping put a new roof on some widow's house that sort of stuff.
Alternately you can go with the, "Handle out my business card" approach. You go back and all you have to do is hand out my business card to people that need help.
Though if I knew the class and race of the particular character in question I could probably give you something better.

Infernal Contract Broker |

Final thought:
I (Pit Fiend's name) will restore you to life whole and hale (i.e. full HP fully rested, no negative levels). For each year you live beyond your resurrection you must kill a demon annually (i.e. first year 1 demon, second year 2 demons, third year 3 demons) due the day before the anniversary of your resurrection. Once every ten years you may ask for another resurrection and partial return of your youth (i.e. 1d10 years taken off the character's age). If you do not complete the terms set forth here you immediately die and have vigor restored lost (THIS INCLUDES THE NEGATIVE LEVELS WE DIDN'T CHARGE HIM FOR BECAUSE THAT IS VIGOR RESTORED... in addition to any poisons purged, diseases cured, hit points restored, years returned, aging penalties denied as conditions afflicting him if resurrected by another after failing to complete the terms of this contract). In no way does this contract offer or imply any claim upon your soul in the case of your demise.
In Good Faith,
(Pit Fiend's Name)
Now of course please note that IF you use the later resurrections that means you've been resurrected twice and owe demons for that resurrection too.
So say in year 11 he takes the extra resurrection:
Now he owes (before year 12) 12 demons. On year 13 he'll owe 14 demons (12 for the first resurrection and 2 for the new resurrection). If on year 23 he takes another resurrection he'll now owe 23+12+1=36 demons before year 24.
Now we don't care HOW he goes about locating the demons but he must KILL them -- not just beat them back from a summons spell. Heck he can call them himself to slay them if he wants... we aren't picky.

Infernal Contract Broker |

Wait, doesn't the pit fiend ALREADY owe the party a favour? A sensible PC would simply point out that the pit fiend is obligated to raise him/her to complete the previous indebtment.
Nothing that isn't covered under contract is owed to anyone. That's the thinking of 'good' people, "Well I healed you so you owe me pray and your soul." In Hell we recognized that any transaction simply covers the terms of that transaction and does not cover the terms of other transactions.
Besides there's a difference between, "hey buddy here's a hand just because we were in the middle of doing something else and it happened to benefit you" and "Here let me cover all the costs of a full blown resurrection for you and drop you off back on your home plane on the way."
I mean they didn't help the Pit Fiend out of the 'goodness' (heh) of their hearts, it just happened to be a consequence of their actions. So he happens to be in a place and offers his help facilitating a deal. That's about even there. We really aren't in the "oh you helped me once without really meaning to so let me gush all over you with unearned praise and help."

Lord Pendragon |

I would have the demon demand that on a certain day at a certain time, the PC and his party go to a certain inn and have a beer. And that is all.
The PCs may or may not find out later that by being at the inn instead of where they would have been allowed a certain street punk to assault a pregnant woman in an alley the PCs would have been walking by and prevented, leading a certain child to never be born.
But that's neither here nor there. The PC is resurrected! Yay!

Iuz the Evil |

Darigaaz the Igniter wrote:"In this box is a button. Push the button, and you get $1 billion. But someone somewhere in the world who you don't know, dies"I would do this. Not even kidding.
And after you did, the box would go on to someone else to ponder the moral dilemma. But don't worry, the Pit Fiend can assure you it will be someone you don't know...
(Cue evil laughter)

Iuz the Evil |

"The Box is a 2009 American psychological thriller film based on the 1970 short story "Button, Button" by Richard Matheson, which was previously adapted into an episode of the 1980s iteration of The Twilight Zone. The film is written and directed by Richard Kelly and starsCameron Diaz and James Marsden as a couple who receive a box from a mysterious man played by Frank Langella who offers them one million dollars if they press the button sealed within the dome on top of the box. However once the button has been pushed someone, somewhere, will die."
Wiki info, but that's the reference.

Valandil Ancalime |

The box is way to obvious. Help others in the Pit Fiends name or just do something seemingly innocent are good (or is that evil) ideas.
I am running RotRL, and plan on doing JR(modified for level) next. They are currently in Runeforge.
The character is a CG Rogue/Shadowdancer, who had dedicated his life to Desna and Ameiko Kaijutsu, even before he(or the player or me)...
The player is smart and won't fall for any obvious traps. He always says, "Never make a deal with a devil(ie: evil outsiders) or dragons."