Chapter One: Necrology
Like all undead, Ghosts have a connection to the negative energy plane. This energy sustains them and will rejuvenate them should their spirits be dispersed in battle. Of all the undead creatures I have studied, ghosts are the most tenacious and difficult to lay to rest (And I include the mighty lich and vampire in my tally!) due to their ability to rejuvenate (More on this in Chapter Three)
Of all undead creatures, Ghosts possess the greatest number of possible reasons for manifestation (We will use the term manifestation rather than reanimation in this section, as it is a much more accurate term). However, for ease of reference, we will simplify them into four categories. "Anchored Spirits", "Echoes, "Emotionally-Charged Spirits", and "Spirits with Unfinished Business".
The Anchored Spirit is one that is bound to a creature, location, or object. Typically, these spirits serve as guardians against theft or harm. The way in which a soul becomes anchored to a specific thing is a subject that is muddy at best. There is no guaranteed way to cause a soul to rise as a ghost after death. However, in most of the cases that I have studied, the binding was performed
without spells, through a simple spoken oath. Typically, neither party was aware that such a binding occurred until after the oath-taker became deceased. When dealing with an Anchored Spirit, one should research the details regarding this oath, as it might provide a clue as to how to lay the spirit to rest. Anchored spirits are not always evil in temperment, but every effort must be made to grant these souls the eternal rest they deserve.
Echoes are not technically Ghosts, but I felt it necessary to include them in this section. These are not true manifestations of a person's soul, but instead an imprint of emotion given a semblance of life by a necromancer. Unlike other types of Ghosts, an Echo cannot rejuvenate on it's own, requiring the necromancer to expend more spell energy to recreate his twisted mockery, they typically also do not have all the powers and abilities of a true Ghost. Without fail, all Echoes are evil of temperment, their personalities subplanted by the necromantic ritual used to give them unlife.
Emotionally Charged Spirits are ghosts who manifest due to their souls being ignited with a sufficient amount of emotional energy at the time of their death. Although the most common emotions to cause manifestation are hatred, anger, and sorrow, there have been cases where emotions such as loyalty or love have caused a spirit to manifest. Emotionally Charged Spirits may or may not be evil in temperment, dependant upon the emotion that manifested them (See Chapter Three for more details).
Spirits with Unfinished Business are ghosts that, unsurprisingly, have unfinished business. Some task keeps them from the grave, and usually only the completion of this task will allow the soul to rest.
Chapter Two: Powers and Abilities
Spirits have a plethora of powers, and you should be aware that even the least spirit can utilize some or all of these powers.
All spirits have the ability to fly, even if they choose to walk. Keep this in mind should you need to do battle with one.
As spirits are incorporeal, they cannot be harmed by non-magical weaponry, and even magical armaments are only about half as efficacious as they should be. The spirit is also protected by an aura of unlife, which can push aside bolts or blades that might otherwise strike it. This same ability also grants them the power to move through solid walls or doors as easy as you or I walk through a field.
Many spirits can chill a creature down to the soul with a mere glance. This particular ability attacks the victim's force of personality, instilling them with an unshakable sense of dread, as well as necrotizing his flesh and causing severe pain. Those who are strong of body can usually resist such an attack.
Spirits can also focus this ability into their hands, reaching out to touch a creature. To my knowledge, only magical defenses will protect one from this touch of corruption. Even the strongest warrior can be laid low by this particular power.
The keening wail of a spirit has been known to instill a sense of panic in those who hear it. Although you are a Companion and should be capable of shaking off such fear through your unflappable faith, keep in mind that your non-Companion comrades might not have such devotion.
Sometimes, the mere appearance of a spirit can cause a living creature to be faced with his own mortality. Those who are not strong of body might find themselves wracked with phantom pains similar to those suffered by the elderly. Agility, strength, and fortitude are all aversely affected by this ability.
Almost all spirits have the ability to move objects through sheer force of will alone, hefting heavy objects and throwing them about (Usually at you!). Keep in mind that any object or persons nearby could be used as a weapon by this creature.
The most feared ability of a spirit is it's power to possess a living creature. It will swoop down upon an unsuspecting foe and enter their body. Only through force of will can one resist this technique (Although certain spells that protect the mind will also render one immune). After this occurs, the only means of saving your comrade is through an exorcism.
Chapter Three: Psychology
To be fair, the psychology of most spirits is similar to their living counterparts. They have hopes, desires, and fears. However, this section will be dealing with the unique alterations in personality that certain spirits gain once they manifest.
Anchored spirits typically act the way they did in life, however, the thing they are bonded with becomes an obsession. The harm or theft of whatever they have bonded with will likely send the spirit into an unholy rage, causing it to attack.
Echoes are, as I have stated before, negative emotion given shape and form. Pity these poor mockeries of life not, for they are but a manifestation of a necromancer's evil will, regardless of what person's shape it takes upon manifestation.
Emotionally Charged Spirits have little else other than the emotion that gave them form. Although they retain their personality and memories, overwhelming hatred or rage might subplant whatever goodly inclinations that they possessed in life. Still, a personal entreaty might reach them, calming them enough for you to enact whatever plan you have. Given time, even a Paladin given form by rage or revenge will succumb to these emotions, twisting his once noble spirit to a thing of evil.
Spirits with Unfinished Business unsurprisingly become obsessed with whatever task they left undone, doubly so if such tasks seem impossible. This might drive the spirit to madness over time, so one should take great care in dealing with these unfortunate souls.
Chapter Four: Tactics for the Companion
Although direct combat is usually only effective against Echoes, various techniques will be described here in order to assist you should you be forced into a confrontation with one of these spirits.
Open Combat: Enchanted weapons and magic are the only things that will harm a spirit, so if you find yourself in battle with one, make sure you have either one at your disposal (But both would be better!) When facing a spirit, armour will not protect you. If necessary, shed the unnecessary weight and have a comrade (Or potion) increase your agility, or cast wards of protection upon you.
Stealth and Tracking: Tracking a spirit may seem an impossible task, given their incorporeality, but you would be pleasantly surprised to learn that it is not. Spirits leave behind a spectral residue known as ectoplasm wherever they go. Learn to spot this sickly, pasty substance, and you will learn to track the ghost. Ghosts have keen senses however, and many traps will prove worthless against them unless imbued with positive energy. Still, should you manage to get the drop on them, I would advise you coat your blades in holy water and dump as much on the spirit as you can. The properties of holy water have been known to interfere with the delicate fabric of negative energy that these creatures are formed from.
Spellcasters: Spellcasters are an incredible boon against a Ghost, as their protective wards against negative energy can prevent you from succumbing to many of the spirits abilities. Spells that shape Force will also be effective, as it will strike true against the spirit regardless of whether it has manifested fully on the corporeal plane or not.
Divine Presentment: Spirits are tricky when it comes to divine presentment. Although the weakest of such spectres can be turned by a priest capable of casting from the fifth circle, stronger specimens require an incredible devotion, and some may seem to be entirely immune!