Insula
A vast continent filled with monsters and magic. Insula consists of ten countries, each with it's own people and culture. This is just the over world, there are also nine more realms that are connected by the world tree. These realms are smaller and less inhabited. This universe is ruled by Norse gods and goddesses (Mostly).
Fantasy
Way far back at the beginning of time, there were three gods, Odin, Thor, and Loki. They each created different realms and they connected them by growing the world tree (a magical tree that people can use to transport between realms). They also magically created more gods (Such as Freya, Hel, etc.). And they each created animals, and monsters to live in their world. Hel (The shadow god) broke apart from the rest of the gods, several other gods sided with her too. Then the god wars began. Hel thought that the world must be equally balanced between dark and light, she created all the evil in the world, but she couldn't control it. That led to her downfall, she was banished to her own realm, the shadow-realm. The other gods were forced to roam Insula with most of there magical powers stripped from them.
The laws of physics are similar to earth's physics in the over world. But in some realms, it's different.
Basic magic like realm traveling, can be mastered by all creatures. But in order to use advanced magic, you need to be a wizard or a god.
So far, gunpowder hasn't been invented yet. Insula currently has medieval technology.