Chaosmancer> If I may, how do you ensure that the PC continues working on the entities behalf? If the PC is unwilling, why not just agree with the entity when it threatens to eat everyone on the PC's friends and family plan? Then, when the entity leaves, the PC can renege? How far can the GM turn the screws on the PC?
These have all been PC's I've made and never gotten a chance to play, if I'm being up front. For example, here is the background for Natalie Dumein Fiendish Bladelock, Human Noble
[sblock] Natali was not born into the nobility, her family was poor and struggled through life working the lands around the Dumein estate. However, they believed their fortunes greatly changed when their daughter caught the eye of the young lord of the eccentric family. Taken to the manor and trained in the arts of nobility, including proper dancing, swordplay and manners, Natali eagerly awaited her wedding and the prosperity she could bring to her family. Immediately after the ceremony though, the family revealed its true intent. Long ago their ancestors had captured a dark being of great power, sealing it within a dark and twisted tree on the estate. It would give them prosperity as long as they sacrificed a noblewoman to it every decade, but if the blood of the family was ever offered its service was over. She was not truly of the blood, but her marriage made her a noble and she would appease the beasts hunger. Natali fought back, grabbing her husband’s blade and running him through. As the blood soaked into the tree everything went black. When Natali awoke she saw a great oozing shape tearing the Dumein family apart, but when it turned to her it instead offered a deal. When the family had it imprisoned it, they had stolen its many golden eyes and sold them across the world. If she wished to live, and not see it rampage through the village to kill the peasants, she would serve it and find it’s 1,000 eyes. She agreed, the rapier in her hand turned an inky black and her hand burned with the pact seal. Her master settled into the manor, keeping up the pretense that the Dumein still ruled and Natali set forth desperate to find someway to escape her new fate, but also gathering the eyes as promised, lest the beast wreck vengeance upon her home and it’s people.
At the time the adventure starts, Natali will have found 5 of the eyes, and her quest would have been going on for 4.5 years. Two of the eyes have been returned to the demon, while the remaining three are on her person. The eyes are orbs of pure gold, about the size of a baseball, with a streak of onyx buried within to act as the pupil.
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The end goal is clearly to find a way out of the pact, another character I've thought of draws inspiration from Nami from the Anime One Piece, a demon has taken over their hometown, and made a game out of this. The PC was given power, a corrupting power that may overwhelm them, and can buy the lives of the townspeople, for 10,000 gold each or something like that.
The idea of being on an impossible quest.
But yeah, they could theoretically renege on the deal, leave and never return, and depending on the pact and story, the consequences can range from nothing to running from this thing that is tearing about the countryside looking for you. It depends on how the player wants the story to begin and then what makes sense to continue, while giving the player free will without their patron being present for every use of their power.
Plus, if all your power comes from this one source, how do you level up without returning to the source, and how can you pull the Ghost Rider and Spawn storylines and turn against your creator? Powerful and clever beings with servants can do all sorts of things if I need them to, but I like it being in the hands of the player.