This story by the Brothers Grimm has so many morals, it's hard to say which one is the main theme. There is the boastful miller who wants to appear important, there is the greedy king who threatens and bullies the miller's daughter - there is the daughter who makes a rash promise, and then there is the Rumpelstiltskin himself, magical, wild, and so full of rage when he loses his bet, that he comes to a NASTY END.