Mamea

Souls are a curious thing.  We think of them as abstract concepts and senses of self, the thing that are 'us' at the same time, and that they're what goes to the afterlife when our bodies die.  But odd people have odd souls, and sometimes, they're more interested in hanging around.

These are Mamea, and they are not to be confused with mere ghosts and spectres.  Ghosts and things of that nature are oftentimes bound my memories or desires.  Feelings.  They are the ESSENCE of a person, that utilizes a soul for power, holding it hostage to do the bidding of the essence of the dead person.

Mamea aren't bound in any way though.  They're merely souls that have chosen to remain in this world.  Well, 'chosen' might not be the right word, as they usually must escape Reapers and other things.  That is why they are so rare.  The temperament of a Mamea is difficult to just 'say' as they're as diverse as people.  because they ARE people.  Some of them are helpful, influencing probability to let things go someone's way.  But some are hostile, and their most common method of attack is possession.  But, this isn't normal possession because it isn't a demon, or a ghost.  Being an ACTUAL soul makes it extremely difficult to even detect that this was actually a possession, even to the one being possessed, and its even harder to eject, due to the risk of forcing the owner's soul with it. 

Mamea aren't usually visible to the naked eye.  It takes a special kind of person to see them, and what it takes to be that kind of person is unknown.  Some say they are blessed by an ancient god to see people's souls, not just the masks they wear.  Some say that people who can see Mamea are destined to become reapers in the afterlife.  While there are methods for making them visible, one should always be cautious because you never truly know what they may do.