A ghost is a form of energy. It is also known as nominative energy.
A ghost is a complex structured energy state which is able to affirm its own existence. Nobody can willingly create a ghost and only very skilled mages can bind them.
Ghosts are often mentions with dead people or souls. Most scientist assure that they have nothing to to with them. Even though no one claims to know what happens after death.
Another reason for this misconception can be the so called aura of the ghosts.
A ghost can’t be seen by normal eyes but most can see and feel to disruption in space. It is also known that ghosts can life or posses living creatures. These will get permanent damage is form of how they move or speech impediments.
A ghost can be used as a catalysator for energy transfer. It is also possible to use the energy of a ghost if it is fully bonded to certain runes.