I think Stephen Fry summed it up quite well where he said there were two specific themes in all Legendary tales, either of 'punishment from high' (which he defined as the Christian legacy, such as the expulsion from Eden) and the 'They're no better than us' fable (such as many Greek legends), and that all these tales told an interesting story about the development of the countries that extolled them.
Magic Fantasy, such as Dragon Age, Neverwinter Nights or Oblivion all follow very much the same rules, the original stories were basically morality plays, like a 1600 page version of 'the boy who cried Wolf', they are usually tales of either redemption or responsibility, and the Dragon (at least in Western culture), in many ways, was a personification of 'bad morality', burning homes, 'destroying' virgins, stealing and hording gold, Consdering this type of Fantasy was at its original height in the 16th Century, it's no real surprise that this is also the time that modern conceptions of Hell, Satan and Demons was formed, there's a definite similarity.
As an interesting aside, I found it personally fascinating that, pre-16th century, the UK was much more rural in nature, the enemies of smaller communities were famine, pestilence and, to a lesser degree war (note the Horsemen of the Apocolypse idealogy rearing its head), however, come the 16th Century, more and more people were living in cities, and a new additional enemy reared its head, fire, which wasn't nearly the threat to small rural communities as it was to a large urban one. Just an interesting note
