"It’s not permitted for any of us to dally with mortals any longer, of course. The treaty put a stop to that. But our children’s lines still continue from millennia ago – they’re races of their own now. The house-elves are rather a bit of an interesting exception, in that they’re pure imps, not cross-bred with anything. They were brought to earth as bound servants for the more high-ranking and powerful of our children. The goblins’ imps died off over a thousand years ago – the goblins couldn’t provide enough magic to sustain them. Imps aren’t as powerful as most of us you’ve met – they need a constant influx of power to remain on earth as their natural reserves are small. I’ve only heard of one or two imps who were ever able to attain the rank of President – the lowest rank – and they didn’t hold it for long."