Here's the first one.
Keres
In Greek mythology, the keres were the children of Nyx and Erebus. Nyx was the goddess of night, and Erebus ruled that part of the underworld inhabited by the shades. The keres were closely related with the Moirai (the Fates) and the Erinyes (the Furies). They served Ares, measuring the fate of each warrior and dragging off the corpses of the dead. They also appeared as goddesses of death, often identified with the avenging Furies.
Popular tradition, however, identified the keres with evil spirits of the dead, perhaps ancestral spirits, who had to be appeased by sacrifices. Entire holy days, such as the festival of Anthesteria were set aside for such sacrifices. The festival closed with the command: "Out of the house, ye keres."
If the keres were not properly appeased they would roam the earth bringing misfortune, disease, old age, and death. In popular belief, the keres were one of the plagues that escaped from Pandora's box. The root "ker" means: "bane, evil, death."
The various accounts of the keres from Greek mythology have inspired an undead monster by the same name.
Keres
CLIMATE/TERRAIN: Any
FREQUENCY Very rare
ORGANIZATION: Minimal
ACTIVITY CYCLE: Largely nocturnal
DIET: Carnivore
INTELLIGENCE: High
TREASURE: Nil
ALIGNMENT: Any evil
NO. APPEARING: 1 or 3
ARMOR CLASS: 1
MOVEMENT: 12, Fl 18
HIT DICE: 9 + 9
THAC0: 11
NO. OF ATTACKS: 3
DAMAGE/ATTACKS: 1d8
SPECIAL ATTACKS: Bad luck, aging, and disease
SPECIAL DEFENSES: + 1 or better weapon to hit
MAGIC RESISTANCE: Nil
SIZE: M
MORALE: Fearless (20)
X.P. VALUE: 7,000
Keres are malignant undead spirits who seek revenge against the living. They look like horrible, black-winged humanoids with gleaming fangs and long, pointed nails. They are dressed in blood-stained robes and carry scourges (barbed whips).
Combat: An attack by keres will be either one ker (the singular form of the word) alone, or a group of three keres. While characters could conceivably chance upon the keres by accident, the undead monster usually is specifically stalking the characters. An attack by a single ker usually will be the spirit of some NPC or monster the characters recently killed. An attack by three keres is often a retaliation visited upon those characters who have become overly bloodthirsty. This latter kind of attack may even be sent against the characters by the gods as a warning. Likewise, keres may be sent as retribution against characters who have proved overly greedy. Thus, there is an element of fate in most keres attacks.
Keres can strike three times per round with their whips. Each attack does 1-8 points of damage. The first attack could, in addition, bring the victim bad luck. The second attack might age the victim. The third attack could infect the victim with disease.
Victims are allowed a save against the additional effects of the attacks. The save against bad luck is the same as petrification. The save against aging is the same as death. The save against disease is the same as spells.
Bad luck lowers all attack rolls and saves of the victim by - 1 to - 4 (roll 1d4) for 3d10 turns. Aging will age the victim 10d4 years. The disease caused by the keres is the same as that imparted by the rotting touch of a mummy. Multiple hits are cumulative.
Keres will fight on until they are reduced to 0 hp or they have slain all the characters. If they are victorious, the keres will drain the blood of their victims then tear the corpses into pieces and devour them, even the bones. There will thus be nothing left of the victims to later raise or resurrect.
Keres can shapechange themselves into tiny gnat-like creatures so they can better stalk their victims. In gnat form they can fly at a speed of 18") but only for a maximum of six turns. If they are not spotted, Keres may follow their victims and wait to attack when the victims are otherwise occupied (usually with another combat). Keres cannot attack in gnat form. The transition takes one round.
The following spells or attack forms have no effect on keres: sleep, charm, hold, cold, poison, and paralysis. They take only half damage from electricity. A cleric has the same chance to turn a keres as she does a ghost.
Habitat/Society: Keres have no particular society. They may have memories from when they were alive and still believe in the dictates of their once-living society. For example, a hill giant is slain by the characters and comes back as a keres to attack his slayers. The keres still will have the same superstitions as the original hill giant.
Sunlight does not harm keres, but they prefer to attack at night. During the day they remain in gnat form, in some hiding place.
Originally appeared in Dragon Magazine #210 (1994).