A lesser spirit of the dead, the kuei is a manifestation of a human or humanoid who died by violence unavenged or with a purpose unfulfilled. The spirit’s former body was not buried.

The kuei looks exactly as it did at the time of death, wearing the same clothes and appearing to be the same age. The spirit looks solid, but cannot be touched; objects pass harmlessly through it.

A kuei speaks the same languages it did in life, but its voice is flat, emotionless, and monotone.

Combat: The powers of a kuei depend on its Hit Dice. These powers are summarized on the table below. The approximate chance of encountering any particular kuei is as follows: 3 HD (10%), 4 HD (20%), 5 HD (40%), 6 HD (20%). The DM is free to make exceptions to these chances if a kuei is derived from a particular character; for instance, if derived from an exceptionally powerful character, the kuei probably would have 6 HD, while a kuei derived from a relatively weak character would have 3 HD.

Kuei can become ethereal at will. They also have the ability to possess; this power can be used three times per day. They are immune to ESP and all charm, enchantment, illusion, and waterbased spells. They suffer no damage from normal fire and cold attacks; magical fire and cold attacks cause only half the normal amount of damage.

When encountered, a kuei normally attempts to possess a victim, usually the person who appears to be the most healthy and formidable opponent. If the kuei succeeds in inhabiting its victim’s body, the spirit’s own form disappears. The kuei then uses the physical body of the victim to complete whatever task still binds it to the Prime Material Plane. While in control of a victim’s body, the kuei uses its own powers and its abilities; it cannot use the abilities of its victim.

The kuei’s possession can be broken by three means: the death of the victim, fulfillment of the spirit’s task, or an exorcism spell (or a similar spell intended to drive out spirits). Once the possession is broken, the victim returns to his normal self with no knowledge of what has transpired.

Habitat/Society: The alignment of a kuei depends on the nature of the task it must fulfill. Typical tasks include seeking vengeance on its killer, fulfilling an oath, or arranging for the temple ceremonies that are necessary for its release. While attempting to fulfill an oath, a kuei can inhabit its victim’s body indefinitely. For example, a kuei who must complete an oath of marriage might inhabit a bride’s body and reside with her husband until the ruse is discovered – which may take years if he’s inattentive.

Kuei roam the world endlessly. They have no permanent lairs, nor do they collect treasure. They usually appear within a few miles of the site at which they died, but they literally can be encountered anywhere – from the frozen wastelands of the arctic to the hottest desert sands. Although kuei are not affected by sunlight, they are most active at night.

Ecology: Kuei neither eat nor sleep; their inactivity during the daytime is more akin to meditation than rest. If they are inhabiting a victim, however, they may go through the motions to avoid being discovered.

Kuei rarely associate with other creatures, though they sometimes accept the advice of evilly-motivated characters who direct them to suitable victims.