Yuan-Ti
One of the most insidious aspects of the yuan-ti is their human heritage, for this vile race of serpent folk is descended from humans who interbred with an ancient sauroid race. In their monstrous evil, the yuan-ti continue this mingling of serpentine and human blood, creating two types of agents and servitors who are not quite human nor fully yuan-ti.
These servitors are created by essentially the same process. If the process is a success, the result is a tainted one. These creatures appear just as they did prior to their infection - generally able-bodied humans (rarely elves, dwarves, orcs, or other humanoids), usually of 3rd to 6th level. Though their bodies do not show signs of their tainted blood, their personalities and mannerisms do: they often develop habits such as frequently licking their lips, drawing our their sibilants, or keeping large serpents as pets. Tainted ones serve the yuan-ti as agents who can pass unnoticed among other races and infiltrate where even a pureblood yuan-ti might risk discovery.
If the process goes awry, the result is a broodguard (called a histachii by some. These near-mindless abominations are hairless creatures with emaciated bodies. Their gray or yellow-green skin is rough and scaly, and smells faintly of rotting meat. They have beady, bloodshot eyes, and their forked tongues continually dart in and out of their mouths. Broodguards, as their name suggests, are most often found guarding yuan-ti brood chambers.
Tainted ones and broodguards speak the languages they knew before their transformation, and usually learn Draconic within a few months of becoming infected.
Creating a Yuan-Ti
"Tainted one" and "broodguard" are templates that can be added to any human (referred to hereafter as the "base creature"). The templates use all the base creature's statistics and special abilities except as noted here.
Hit Dice: As base creature.
Speed: As base creature.
AC: As base creature. Broodguards do not wear armor.
Attacks and Damage: As base creature. Tainted ones also gain a poisonous bite, but this is useless in most combat situations (see Special Attacks).
Broodguards have sharp claws and vicious bites they can use in melee. They use the base attack values they had as humans, but their claws deal 1d2 points of damage and their bite deals 1d3 points of damage.
Special Attacks: Tainted ones and broodguards retain all the special attacks of the base creature. Tainted ones also gain the following two special attacks:
Psionics (Sp): The transformation activates latent psionic potential in human minds, granting tainted ones supernatural abilities similar to those of true yuan-ti. A tainted one can create the following effects through the power of its mind as a sorcerer of its character level: poison (Fortitude save against a DC of 13 the tainted one's Constitution modifier) and polymorph self (into snake or snakelike forms only).
Poison Bite (Ex): The saliva of a tainted one is poisonous when ingested or introduced into the blood, though this ability is generally useless in combat. A tainted one can only inject its venom 4 while grappling a foe with exposed skin. The Fortitude save to resist this poison has a DC of 10 + 1/2 the tainted one's Hit Dice + its Constitution modifier. Victims who fail this save take 1d4 points of temporary Constitution damage. After 1 minute, they must make another save; failure means another 1d4 points of temporary Constitution damage. A tainted one's kiss is also poisonous, though in this case the save DC is reduced by 2.
Broodguards do not gain these special attacks, but instead gain a rage ability:
Rage (Ex): Once per day, a broodguard can enter into a berserk stare similar to a barbarians rage. In this state, the broodguard gains +4 to Strength, +4 to Constitution, and a +2 morale bonus on Will saves, but it suffers a -2 penalty to Armor Class.
Special Qualities: All the special qualities of the base creature, plus the following:
Poison Immunity (Ex): Tainted ones and broodguards are immune to all forms of snake venom, including their own poison.
Spell Resistance (Ex): Tainted ones gain spell resistance of 5/+1 per three levels.
Mental Resistance (Ex): Broodguards are immune to hold and charm spells.
Saves: As base creature.
Abilities: Tainted ones gain +2 to Constitution. Broodguards gain +2 to Dexterity and +2 to Constitution, but lose -4 Intelligence and -4 Charisma.
Skills: As base creature. Broodguards lose 2 ranks in each skill because of their reduced Intelligence.
Feats: Tainted ones and broodguards gain Alertness as a bonus feat due to their heightened senses.
Climate/Terrain: Warm land
Organization: Tainted one: Solitary
Broodguard: Clutch (2-8) or tribe (9-20)
Challenge Rating: Tainted one: Base creature +1
Broodguard: Base creature
Treasure: Standard
Alignment: Usually chaotic evil
Advancement: Tainted one: By character class
Broodguard: -
Creating Tainted Ones
Yuan-ti create most of their servitors from human prisoners. They also may transform human worshipers who voluntarily agree to become tainted ones. Humans become tainted ones by drinking a distillation of yuan-ti venom mixed with certain herbs and roots.
Any human who drinks this mixture, whether by choice or by force, must make a Fortitude saving throw (DC 16). If the saving throw fails, the victim must make a Constitution check (DC 15). Success at this check means the character becomes a tainted one in a painful transformation that lasts 1d6 days. Failure means the character slowly becomes a broodguard in 7-12 (1d6+6) days. If the Fortitude save is successful, the victim immediately lapses into a coma; death will follow in 1 hour. A comatose victim can be revived with a delay poison or neutralize poison spell, if the spell is cast within 1 hour after the mixture has been swallowed. Human-headed yuan-ti have the ability to neutralize poison, and they may save a comatose victim themselves. It is not for the victim's benefit. A human who fails his save after drinking the mixture may suddenly find himself conscious again, only to face another flask of the mixture when the yuan-ti attempt another transformation.
Only humans can become tainted ones. Non-humans who drink the yuan-ti mixture must make the same Fortitude save (DC 16), however. If the save is successful, the nonhuman will be violently ill, unable to take any action for 1d4 rounds. If the save fails, the non-human becomes comatose and dies in 1d4+1 rounds.
If a human fails his saving throw after consuming the mixture, a few desperate measures may prevent his transformation into a tainted one. If neutralize poison, dispel magic, remove curse, and heal are cast on the victim, in precisely that order, the transformation process will be reversed. However, the victim will permanently lose 1 point of Intelligence. A wish, limited wish, or miracle spell will reverse the transformation with no loss of Intelligence. Once the transformation is complete, only a wish or a miracle can restore the victim to his former self.
In The Realms
The process of creating tainted ones was devised by the yuan-ti of the Serpent Hills, and their agents now operate throughout the North. If it has nor happened already, it is certainly only a matter of time before the yuan-ti of Hlondeth and Chult learn the secret as well, and tainted ones will be found throughout Faerûn.
A yuan-ti abomination named Zsrulkk Ssarmn is a leading figure in the slave trade of subterranean Skullport. He has recently completed a temple to the serpent deity Sseth underneath his residence, and is actively breeding yuan-ti and creating tainted ones from his slave stock, apparently with the assistance of a halfblood yuan-ti from the Serpent Hills. Some suspect that he sells tainted ones as slaves to important figures, or allows tainted one slaves to be stolen by other slavers, using them as spies in the houses of his enemies. It is unclear what purpose lies behind this risky practice.
Sample Tainted One: Yuan-Ti Tainted One.
Sample Broodguard: Yuan-Ti Broodguard.