So, while I'm at it, I think I'll do a bit of a lore dump for anyone curious.
Let's start with the Witch-Queen. She appeared about eight hundred years ago and pretty much immediately started causing trouble, teaching a bunch of people magic that no-one really knew about, and declaring her intent to take over the world, effectively. But the Witch-Queen herself was not, in fact, human.
The Witch-Queen was a divine spirit, a few steps away from being an actual god, who descended to the world shortly after its creation. This is why she was such an incredibly powerful practitioner of magic, she had no human limits whatsoever. It was likely by pure luck that she was killed, and even then, there's rumors that she's not actually dead. Whatever the case may be, she hasn't threatened anything since her defeat.
Now for demons.
Demons are, in fact, rebellious spirits who went down to the world too early, before it was finished. Their bodies reflect this, featuring horns and other such features, and their nature altered. Demons are not evil, but often tend to be mischievous and mostly interested in their own enjoyment, and some very much are evil. Demons keep their true names hidden, often taking names based on titles applied to them by others. For example, a demon known as "the Red Bell that Tolls of Doom" has taken the name "Reddebelle".
Speaking of the creation of the world and gods and stuff, there are a couple notable cosmological things to get across here: Firstly, Reon and Mayon are believed to be physically present on the Sun and the Moon, respectively. There's a few other gods with similar beliefs around them. Secondly, Hidroroth, the Enemy of the World, is said to have had his soul torn apart and forced beyond the Door of Creation.
The Door of Creation is the door, well, leads outside of Creation, atop the Thousand Starlight Stairs.