"Fairies are - they're like humans, but they move very fast, faster than people can see, and they have a debt system that - tracks how much they've done for people, and how much people have done for them, and if they do something that fairy thinks is horrible, like lie, then they and everyone who they owe or who owes them will suffer for it. And if someone is in your debt you can hurt them, and if you're in someone else's debt and you try to hurt them then fairy will punish you, maybe kill you for it. And they don't die except by violence, and they don't need to eat anything besides dew, and they can follow paths that make them very small sometimes, and they don't understand what evil is. And you should not interact with them unless you are desperate."