This is uncertain. I know that you react very strongly to things you consider paranormal. If there is magic on Aemudi, it is very slight.Spirits are nearly everywhere. But I believe their home is in between the realms. On my first assignment, I was falling through the well and I looked to my left. There was an eye. An eye so vast, that it was there the whole time I fell.
Spirits are all so different. Some take the shape of glowing orbs, while others are skeletal fish. There are birds with colors too vibrant to be real and small figures of blue fire. Some can even take a human form, though if one looks at their eyes, they can see through the disguise. Their eyes are glowing orange, lilac, or maroon.
If a mortal can find a spirit willing to talk to it, then they can enter into a contract. The mortal will be granted something within the spirit's power, while the spirit will take something that the mortal holds dear. It could be concrete like a treasured possession or something as vague as an opportunity. They are then unbreakably bound to the contract and go their separate ways. Multiple people can enter into one. Sometimes whole races. You must be careful never to go into a contract with a younger spirit. The young ones will trick you into a curse, but older and wiser ones are fair in their dealings.