A little historical background about the Breton city of Ker-Is... All hail Wikipedia!
You learn something every day, I tell ya. I would never have heard about the folklore surrounding Ker-Is (and its possible connection to Par-is !!!) if it weren't for Ys, the video game.
Let's expand (I'd make a new thread, but this might be a short list):
Exile: Templar Knights, Bacchus and Bacchannalian feasts (they spelled it "Bakas" in the game, but we know what they were getting at)
I'm curious about other games that are rooted, however loosely, in folklore/history. For example, there is a HuCard game based on Chinese folklore (it was discussed here a long time ago, but I can't find it the thread) that had a "trickster monkey" in it... it was a platformer. Anyone know the title?