Wraiths

Wraith are the souls of dead clerics, returned to the world of living with magic. They are servant to the magician who had summoned them, and act in their name by turning other people to the way of evil. However, since this means being turned into an undead creature, it usually results in battle. Wraiths are very resistant.

It is impossible to say, where they can appear. Thankfully, with the defeat of Mondain, these unrestful spirits again went back to their graves.