NPC Idea: Rumpelstiltskin's Child

What if Rumpelstiltskin's plan had succeeded and he had ended up with an adopted son? Brought up by an amoral trickster-devil, taught to be able to spin straw into gold and disappear or reappear wherever he desired - but, at his core, fundamentally and irredeemably good because of his kindhearted mother?

He would be ungovernable, untrustworthy, unreliable, unkempt, and uncouth, constantly using his talents in all manner of undesirable ways. Donating vast wealth to a beggar on a whim, with little thought to how the beggar will avoid being robbed the next day. Buying a war galleon and crew to help him realise a frivolous dream of becoming a pirate, roaming the high seas causing mayhem until becoming bored (and often leaving his victims behind, unmolested, on a rowing boat with a gift of a golden necklace and a cheerful, "Sorry!"). Breaking the hearts of young girls by plying them with trinkets before quickly becoming distracted by the next pretty thing to catch his eye, but trying to make amends with inappropriate presents for their mothers. Using his ability to appear from nowhere to spook old ladies and priests.

Alternatively, he would be morose, unhappy, ill-at-ease with the world, forever wary of using his gifts because of a pained awareness that he will draw unwanted attention to himself, and scarred by his upbringing with a wicked father. He would still be unable to resist the urge to perform small acts of kindness - a pinch of gold straw given to a poor urchin here, a donation to a dilapidated temple there, a gift for an old widow, revenge taken on a neighbourhood bully.

Other fairy tale "what if" ideas: Rapunzel marooned in her tower after the witch accidentally dies while on an errand; the seven dwarves are hired to preserve royals in glass before they die so they can live forever.