The world the campaign takes place in is called Fillead. This is the sister world to Earth as we know it. These worlds can be considered, “Alternate Universes,” to each other at the beginning, but sometime early on in the history of the two worlds, each decided to go in different directions.
Earth, the planet we all know and love, decided to go with Science. People abandoned “the old ways,” and started learning about how the world around them works. This leads to what we live in today, with computers, vaccines, cars, any modern technology.
Fillead decided to stay with magic instead of science. There are sorcerers and wizards, and instead of vaccines, the people of Fillead created more and more useful potions to cure everyone. It even has all of the magical creatures that earth used contain.
But the important thing is that on Earth, come creatures felt abandoned by the people who decided to learn about science, and went over to live in Fillead permanently. This is the reason why Earth no longer has Fae and Demons, but Fillead does.