Yuan-ti were originally humans, thousands of years ago, who were transformed into serpent folk through ancient rituals. Most yuan-ti were corrupted into evil-monsters by those rites, but some yuan-ti instead became a new people who mix characteristics of humans and snakes.
Blessed with resistance to magical and poisonous effects by the rituals that created them, each of these yuan-ti manifests their serpentine heritage in a variety of ways: a forked tongue, snake eyes, a snakelike nose, or some other ophidian characteristic.
The appearance of yuan-ti varied greatly from nearly human-like to nearly snake-like, but all have some serpentine features. Scale colors are usually simple greens and browns, but elaborate swirls, stripes, or diamond patterns were possible, even in blues and reds. Yuan-ti give off almost no scent that a human could detect, but animals could sense a dry, musty odor from their bodies.
However a Yuan-Ti looks, they have the power to pursue great good or evil in the world. But to see a Yuan-Ti i wander the streets, would often be met with strange looks, distrust and whispers, due to their history as 'evil monsters'.
The yuan-ti prefer to make their homes in the tropical jungles of Kildar.
Yuan-ti call themselves vrael olo (which means "favored ones"). Daily use typically uses the shortened "vrael", and can be modified to "auvrael" (meaning friendly or known yuan-ti) and "duthrael" (unfriendly or unfamiliar yuan-ti).
In general, the more serpentine features a yuan-ti possesses the higher its status in yuan-ti society.
Yuan-ti culture is centered around their temples, which often were found in ancient ruins. The locations of these temples are well-guarded secrets. Outside their temples, they usually only appear in small groups of less than five.
The Yuan-Ti speak their own fork-tongued language, and use the Draconic Alphabet to write.
The yuan-ti were once human thousands of years ago. Long before humankind dominated the world, a now long gone reptillian race named the Sarrukh created the first yuan-ti by magically experimenting and mixing humans with snakes and other Sarrukh, this also created the Nagas and Lizardfolk.