Tiefling

Tieflings were human-based planetouched, native outsiders that were infused with the touch of the fiendish planes, most often through descent from fiends—demons, Yugoloths, devils, evil deities, and others who had bred with humans. Tieflings were known for their cunning and personal allure, which made them excellent deceivers as well as inspiring leaders when prejudices were laid aside. Although their evil ancestors could be many generations removed, the taint lingered. Unlike half-fiends, tieflings were not predisposed to evil alignments and varied in alignment nearly as widely as full humans, though tieflings were certainly devious.The celestial counterparts of tieflings were called aasimar.
Tieflings tended to have an unsettling air about them, and most people were uncomfortable around them, whether they were aware of the tiefling's unsavory ancestry or not. While some looked like normal humans, most retained physical characteristics derived from their ancestor, with the most common such features being horns, non-prehensile tails, and pointed teeth. Some tieflings also had eyes that were solid orbs of black, red, white, silver, or gold, while others had eyes more similar to those of humans.[13] Other, more unusual characteristics included a sulfurous odor, cloven feet, or a general aura of discomfort they left on others.[8]
In many other ways, tieflings were similar to humans physically. Tieflings were, on average, just as tall as humans, from 5′6″‒6′2″ (170‒190 cm) and weighed just a little bit heavier at 140‒220 lb (64‒100 kg). Tiefling skin was usually human-like in color, though extending past normal human colors into reddish hues as well. Tiefling hair was also often the same color as human hair, though dark blue, red, or purple were common shades amongst the race. Although it was not always the case, tieflings tended to have better reflexes than their human kin. This, along with their natural propensity for hiding and deceit, helped to give tieflings a reputation for thievery and duplicity.
Tieflings who had strikingly inhuman features were often killed at birth by their horrified parents or others. Only those tieflings with subtle features or born to someone indifferent to their appearance, either out of acceptance or cruel purpose, were likely to reach adulthood. Those tieflings who did reach adulthood could be expected to age at roughly the same rate. They had life spans roughly 20 to 40 years longer than normal humans.
The physical appearance of a tiefling often depended on the exact ancestry that spawned it, a bloodline that might have remained dormant for generations. Diabolic or demonic tieflings could, besides the common horns and tails, possess a forked tongue, leathery or scaly skin, the smell of brimstone, or unusually warm flesh. Some accounts even held these tieflings to cast neither shadows nor reflections. Some diabolic tieflings also sported goat-like legs or hooves. Tieflings descended from rakshasa might have furred skin or feline eyes. Most tieflings had only one or two of these features.
Some tieflings were not descended from mere fiends at all, but from powerful gods. These tieflings often had their own physical characteristics that set them apart. Tieflings sired by Beshaba, for instance, often had antlers instead of horns and pale, white hair. Those sired by Mask, on the other hand, were known for their tendency to cast no reflection.
In Mulhorand, the most common tieflings were often those spawned from a union with Sseth or Sebek. Most tieflings were, however, the grandchildren or even great-grandchildren of fiends and in Mulhorand's neighbor, Thay, most tieflings were spawned deliberately by powerful wizards as part of some elaborate plot for power.
Tieflings had a number of abilities gifted to them by their fiendish heritage. By and large, tieflings were alluring and intelligent creatures, with a seductive aura in spite of their obviously evil ancestry. To a large degree, tieflings were more capable of guile than a great number of races, but these were not their dominant qualities.[9]

A tiefling bard singing in battle.
Most tieflings were aware from an early age that they were different from others around them, and were given to strange urges and desires because of their unusual ancestry. Few tieflings were raised with the love a normal human child might expect to receive and this shaped most of the race into bitter individuals who expected eventual rejection from all whom they meet. While some would follow this path towards evil, others rejected it wholeheartedly and sought to make a good impact on the world around them, sometimes becoming the most heroic characters of all. Few could maintain this discipline however, and most tieflings fell somewhere between both extremes.
Because tieflings were generally distrusted throughout the world, owing to their fiendish heritage, many were themselves distrusting and self-reliant. Tieflings were also proud and secretive by nature and possessed a dark demeanor. Unfortunately, this only helped to further the reputation tieflings had for being social outcasts and untrustworthy scoundrels. However, members of other races would find that once they demonstrated friendship and trust towards a tiefling, it would quickly be reciprocated in full. Once that bond was forged, it was rarely broken.
Those tieflings who sought power through arcane magic were most often warlocks.[9] Tiefling arcane spellcasters of all kinds, however, felt a draw towards the fiendish energies of the planes and tiefling wizards commonly specialized as diviners for the purposes of seeking knowledge of the Lower Planes or as conjurers so that they might summon the dark spirits whom they called kin.
Tieflings had an innate resistance to heat and had a hint of bloodlust that gave them a slight edge in combat. Tieflings also had access to an ability known as infernal wrath, which channeled their innate rage and potential for evil into their attacks for added effectiveness. Some tieflings also learned to unlock their fiendish potential further, sprouting wings such as those borne by many fiends.
Some tieflings also had the innate ability to cast a darkness spell, though not all of the race exhibited this trait.