Ghosts are the disembodied spirits (or spectral entities) of people who have died. The exact reasons as to why this phenomenon occurs is unrevealed. One hypothesis is that ghosts and earthbound spirits remain bound to the Earthly dimension due to unresolved issues from when they were alive. Ghosts are also often linked to objects and locations associated with them in life; Cyrus Kriticos (and possibly Plato Zorba in the 1960 movie) was able to gain dominion over twelve ghosts by their possessions, using specially-designed prisons to keep them under his control.
In the films, while it isn't fully specified how they are formed, a deceased person's soul might remain bound to the plane of the living when it's unable or unwilling to cross over to the next plane of existence after death, typically due to unresolved issues. The duration of their stay is indefinite, lasting years or even centuries (such as with Isabella Smith, who's been earthbound since the 18th century). It has been suggested their formation may be the by-product of a high concentration of great, emotional intensity upon their moment of passing.
Appearance and Abilities
In the 2001 film, according to Dennis, most ghosts can't harm the living nor do they really have the desire to, but there are exceptions, such as the ghosts that make up the Black Zodiac, and the ghosts imprisoned in Dr. Zorba's mansion. These ghosts had enough spectral energy to be capable of interacting with the physical world; moving and projecting objects and could actually attack and even kill a living person.
Their appearance as a ghost may vary, though they mostly range from the most recent state they were in when, after or very shortly before they died. Additionally, special objects and devices relating to their persona or circumstances of their death may actually become as part of their apparition such as Jean Kriticos' IV rack, Royce Clayton's baseball bat and car, George Markley's hammer, Harold's axe, Dana Newman's knife, etc. And like the ghosts, these objects can also interact with the physical world as well and may become weaponized without a moment's notice. Therefore, with or without a weapon, they are very dangerous and avoidance was emphasized.
For the 1960 film, the ghosts imprisoned in Dr. Zorba's mansion varied widely in appearance, as some weren't even human. One was the ghost of a lion while the others were merely floating, disembodied limbs and other appendages.
Ghosts are invisible to the human eye and can usually only be seen through specially-made spectral viewers, though there have been some exceptions. In the 1960 film, the ghosts were semi-transparent when seen, while in the 2001 film, the ghosts were fully opaque when viewed through the glasses and faint whispers could be heard whenever they were present.
Personality and Emotions
The ghosts that were imprisoned in Basileus's Machine and Dr. Zorba's house respectively (particularly the former group of ghosts) were shown to be extremely violent and prone to attacking and killing without conscience or reason. According to Dennis in Thirteen Ghosts, this is because ghosts who died violently are left in a tortured realm/state if they do not cross over, and thus they eventually come to know nothing but rage and violence as a consequence.
As strong as these ghosts could be, they're not without frailties. For example, in Thirteen Ghosts, for reasons unknown, ghosts are forced to obey Latin spells and whatever they say, whether spoken or written, though a ghost can resist the spells if they are strong enough. Ghosts were not able cross barrier spells, and spells that command them to travel to a nearby location will force them to go directly to that place.
Notably, in the 2001 film, ghosts such as The Jackal retreat from quicksilver flares and briefly disappear. According to the script, this is because burning metal temporarily disrupts ghosts' spectral energy. Also, in the 1960 film, when Dr. Zorba and the other eleven ghosts were placed in his mansion, they were trapped in the house and could only leave and move on when a thirteenth ghost joined them. The ghosts in the 2001 film, on the other hand, were presumably confined by none other than the barrier spells of Basileus's Machine and were free to roam the Earth once again upon its destruction.
Differences between 1960 and 2001 versions
- The ghosts in the 1960 film, when visible, were semi-transparent, while the ghosts in the 2001 film were opaque when they were visible.
- In the 1960 film, ghosts could become trapped in buildings in which they were placed (until enough other ghosts joined them). In the 2001 film, this rule does not appear to technically apply.
- The noises which are heard when a ghost is present are screaming, gasping and moaning in the 1960 film (the sound of their earthly torment); while in the 2001 film, it is faint, eerie shrieks and whispers (possibly from their colluding with each other).