Magicals are hybrid souls, born when spirits of the dead invade living creatures. Unconsciously the spirit seeks a familiar lesser lifeform, typically an animal or a plant, and attempts to take residence in its physical container.
For nearly all dead people will move on to the Realm of the Dead, it is a rare occurrence that one will become an unstable spirit capable of invading other physical bodies. The exact conditions are unknown, but strong attachments to the material world seem to play a big part. Ironically, though, newborn Magicals typically lose most of their memories when their soul merges with a soul of a lesser creature. Additionally their mental ability and general knowledge usually reverts to preteen level.
As their name suggests, Magicals tend to have extraordinary magical abilities. They are almost always capable of shapeshifting and typically take a humanoid form with some distinctive features from the host organism.
In big cities it is not unheard of that someone’s pet becomes a Magical. Although this naturally causes some confusion, the modern law states that the pet owner must either adopt the newborn Magical or bring her to the nearest Academy of Magic. Many choose to adopt, because the Magical inherits the former pet’s feelings towards it’s master. Some do not, though, for the same reason.