The idea of "supernatural" is funny really...

If something REALLY exists, is it not natural?

At one point gravity, the sun, magnets, the workings of the human body... None of these were within the mental reach of early humans, and indeed they were often thought of as "magic" or "supernatural" manifestations.

But really, "supernatural" is another way of saying "non understood" or "not proven". Because if something exists, it's part of nature.