A lycanthrope is a human with the ability to change his or her shape to some animal form during the night hours. A full moon is 90% likely to trigger the transition to animal form automatically. Any humanoid bitten by a lycanthrope and damaged for 50% or more of its total hp who survives will contract the lycanthropic disease of its attacker. A cure disease from a cleric of 12th level or higher will remove the disease if performed within three days of the attack. If the victim ingests belladonna within one hour after the attack there is a 25% chance the disease will be cured. However, swallowing belladonna in such a manner will incapacitate the victim for 1d4 days; there is also a 1% chance of the herb killing the victim.
A lycanthrope’s “size” stat shows its shapechanged size. In human form they are obviously always man-sized.
Each type of lycanthrope has its own language. The five most common types are listed below.
| Werebear | Wereboar | Wererat | Weretiger | Werewolf | |
| Frequency: | Rare | Rare | Uncommon | Very rare | Common |
| No. Encountered: | 1d4 | 2d4 | 4d6 | 1d6 | 3d6 |
| Size: | Large | Large | Small to medium | Large | Medium |
| Move: | 90 ft | 120 ft | 120 ft | 120 ft | 150 ft |
| Armour Class: | 2 | 4 | 6 | 3 | 5 |
| Hit Dice: | 7+3 | 5+2 | 3+1 | 6+2 | 4+3 |
| Attacks: | 3 | 1 | 1 | 3 | 1 |
| Damage: | 1d3/1d3/2d4 | 2d6 | 1d8 (sword) | 1d4/1d4/1d12 | 2d4 |
| Special Attacks: | Hug for 2d8 | None | Surprises on 1-4 in 6 | Rake for 1d4+1/1d4+1 | Surprises on a 1-3 in 6 |
| Special Defences: | Hit only by silver or magic weapons | Hit only by silver or magic weapons | Hit only by silver or magic weapons | Hit only by silver or magic weapons | Hit only by silver or magic weapons |
| Magic Resistance: | Standard | Standard | Standard | Standard | Standard |
| Lair Probability: | 10% | 20% | 30% | 15% | 25% |
| Intelligence: | Exceptional | Average | Very | Average | Average |
| Alignment: | Chaotic good | Neutral | Lawful evil | Neutral | Chaotic evil |
| Level/XP: | 5/850+10/hp | 4/250+6/hp | 3/150+4/hp | 4/500+8/hp | 3/200+5/hp |
Werebear: A werebear appears in human form as a large hairy human with a solitary disposition. In ursine form, he or she is 50% likely to be accompanied by 1d6 brown bears. A werebear may summon 1d6 brown bears in 2d6 turns if they are within one mile. Werebears are immune to disease and heal three times faster than normal. They can also cure disease in another creature within 1d4 weeks.
Treasure: 2d4×1,000 gp (40%), 1d6×100 pp (50%), 4d8 gems (55%), 1d12 jewellery (50%), 1d4 scrolls + 1 misc. magic + 1 potion (60%)
Wereboar: A wereboar has a foul tempered disposition in either form and will attack in a frenzy. It is found in heavily wooded areas, but rarely with normal boars (15% chance of 1d4 boars that will attack on direction by the lycanthrope).
Treasure: 1d8×1,000 cp (50%), 1d6×1,000 sp (25%), 1d4×1,000 ep (25%), 1d3×1,000 gp (25%), 1d8 gems (30%), 1d4 jewellery (20%), sword, armour, or misc. wpn +2d4 potions (40%)
Wererat: The horrid ratmen infest the underground sewers and catacombs under large cities. They are stealthy and surprise on a 1-4. They can assume any of three forms: human, giant rat, or man-rat. In human or man-rat form, they often arm themselves with swords, but prefer to lure unsuspecting individuals into traps where the victim may be held for ransom or later meals. A wererat may summon 2d6 giant rats and control them. Rumours persist of a city of black wererats on a remote shore; the more fanciful tales suggest the black wererats may have powerful spellcasters among their number who can magically affect the phases of the moon.
Treasure: 1d12×1,000 cp (20%), 1d6×1,000 sp (30%), 1d4×1,000 ep (10%), 1d6 gems (25%), 1d3 jewellery (25%), any 2 magic items (10%)
Weretiger: Most weretigers are female and live much like a normal tiger does, though associating with the normal breed only 5% of the time. They can rake with their rear claws like a normal tiger. All normal cats are 75% likely to be friendly to a weretiger due to the lycanthrope’s ability to speak with them.
Treasure: 1d8×1,000 cp (10%), 1d12×1,000 sp (15%), 1d8×1,000 ep (15%), 1d6×1,000 gp (50%), 2d6 gems (50%), 1d6 jewellery (25%), any 2 magic item + 1 potion (15%)
Werewolf: A werewolf may be of either sex and of any build. When in wolf form, the lycanthrope tends to walk on its back legs. If a werewolf pack numbers 5 to 8, then it will be a family pack which consists of a male, a female and 3-6 younger werewolves ranging from 60% to 90% mature.
When in its pack, the male will fight at +2 and deal full damage if the female has been attacked. The female will attack with a +3 bonus to hit and will do full damage if her cubs are threatened. The cubs will attack with a penalty of -4 to -1 depending on their stage of maturity and deal 1d4+1 hp per attack. Any pack may also include wolfweres (wolves who can assume human form).
Treasure: 1d8×1,000 cp (50%), 1d6×1,000 sp (25%), 1d4×1,000 ep (25%), 1d3×1,000 gp (25%), 1d8 gems (30%), 1d4 jewellery (20%), sword, armour, or misc. weapon (10%)