Doppelganger

Doppleganger

Species	humanoid
No. Appearing	3–12
Behaviour	insurgent
Range	subterranean, urban
Size	6 ft. tall (non-shifted)
Weight	160 lbs.
Intelligence	12 to 13
Armour Class	5
Hit Dice	4
Action Points	5
Max. Stride	8
THAC0	18
Hp/Die	d8
Attack Forms	fist or by weapon type
Damage	1–12 or by weapon
Special Attacks	natural immunities, not surprised, save as 10th level, shape change, strength, surprise on a 1–4, telepathy

Doppelgangers are shapeshifting, bipedal humanoids consumed by an insatiable craving for power. Malevolent and devoid of morality, they achieve their ambitions through deception and murder, preying upon those in positions of influence. Their preferred method is to assassinate individuals of authority and assume their identities, manipulating the unsuspecting populace to serve their own ends. Many whispered tales speak of entire towns or organisations unknowingly ruled by doppelgangers, their beloved leaders long dead, their bodies left to rot in hidden tombs or dissolved in lime pits.

A doppelganger can reshape its body to mimic any humanoid between 4 and 7½ feet tall and up to 400 pounds in weight, including an imitation of the victim's clothing and external features. Their mimicry extends to voice and mannerisms, and they can even steal fragments of their victim's recent memories through ESP, gaining enough knowledge to pass as their target convincingly. While doppelgangers can replicate many humanoid traits — such as the correct blood colour or feigning exhaustion — they do not actually require sleep.

However, if seriously wounded, their disguise falters, revealing a glimpse of their true form where they were struck. A doppelganger's illusion is impervious to most forms of detection, though it can be unmasked by penetrate disguise, provided the caster is at least 5th level. For this reason, doppelgangers tend to avoid infiltrating high-profile political entities, where magic-wielders might expose them, instead preferring smaller, isolated settlements where their deception is less likely to be uncovered.

When exposed, a doppelganger will immediately attack before fleeing, rapidly shifting between different humanoid forms from past disguises. Blending into a crowd provides them with ample opportunity to escape, as they are adept at feigning helplessness or innocence to throw off pursuit. Their ability to become nearly anyone at a moment's notice makes capturing or killing them a formidable challenge.

These creatures rarely work alone. Where one is found, others are likely present, embedded within positions of authority. Unravelling a conspiracy of doppelgangers is a perilous undertaking, as their network is deeply rooted and highly coordinated. Knowing this, doppelgangers often attempt negotiation when confronted, presenting themselves as an unstoppable force with influence too entrenched to uproot. They frequently offer their would-be enemies a "mutual understanding," suggesting that it is far easier to coexist and benefit from their rule rather than struggle against it. To those who dare challenge them, they extend a simple but chilling proposition — deal with us, or be replaced.

Advantages

Dopplegangers are unusually strong, possessing an 18 strength (+1 to hit, +2 to damage). When pummelling, they do not benefit from their strength bonus but still inflict 1-12 damage. This same 1-12 damage applies regardless of the weapon they wield, provided the weapon weighs at least 3½ lbs. For example, both a long sword and a short sword will deal 1-12 damage, as will a battle axe. However, when using weapons, doppelgangers do gain their strength bonuses, further increasing their lethality.

A doppelganger's ESP is a continuously functioning natural ability, allowing it to sense the thoughts of anyone within 30 feet. If someone nearby begins to suspect a doppelganger, the creature will immediately become aware of it. Likewise, it will detect plots against it, including attempts at backstabbing, assassination or those moving with stealth in its presence. As a result, a doppelganger is never surprised.

The only effective way to confuse a doppelganger's ESP is to attack when it is surrounded by a large crowd, where the sheer number of conflicting thoughts can make it difficult to focus. However, this also means striking at a leader figure in the midst of their followers, making a direct confrontation even more perilous. Additionally, the doppelganger's ESP is limited to 30 feet, so ranged attacks from beyond that distance can bypass this advantage. For this reason, doppelgangers avoid open spaces and prefer small, enclosed rooms with heavy drapes covering the windows. They do not take solitary walks outdoors or even in long hallways, a subtle but noticeable habit that may arouse suspicion among those who observe the sudden change in behaviour of a recently replaced leader.

Doppelgangers also use their ESP to determine the perfect moment to attack, which is why they surprise on a 1-4. They will patiently wait until their target's thoughts are preoccupied — lost in concentration, deep in conversation or otherwise distracted — before striking. Their preferred method is to pose as a servant or other menial worker, gaining access to high-ranking individuals before murdering and replacing them at the most opportune moment.

These creatures are also immune to sleep and charm, whether from magic or other influences. They possess remarkable endurance and make saving throws as though they were a 10th level fighter, making them highly resistant to many forms of magical and physical attacks.

See also,
Bestiary
Recognise Doppelganger (sage ability)