Tieflings are the offspring of devils or demons and a mortal race. Often distrusted due to this connection to the hells, Tieflings are however their own people and are not all as evil as their demonic parentage.
All Tieflings have infernal bloodline. Commonly this is due to a parent being a devil or demon of some sort, the mortal parent is almost always a human due to the ease of interbreeding, but some elven tieflings have been known. Tieflings can also be born of other tieflings, as tieflings always breed true, but only with other tieflings.
This infernal heritage has a clear effect on their appearance, this blood from the lower planes leads to a great variety in tiefling appearances. Some have long, barbed tails, others have large rams horns, pointjed ears, round ears, cloven hooves similar to a satyr, goats horns, scales, wings, many eyes, 1 eye. It's said that no two tieflings look alike. The easiest indicators are their eyes, which are almost invariable a solid color — black, red, white, silver, or gold — with no visible sclera or pupils. Skin tones also cover almost the full rainbow, but usually settle on common human skin tones, shades of red, purple and charcoal gray.
While Tieflings are rarely seen on the Prime Material planes, the outter and inner planes are lousy with them due to both sides,but primarily demons deciding creating more of “their kind” a good way to win the blood_war. When a berk from the prime material reaches beyond the prime and material planes, they often are surprised by how many Tieflings they will see. While they do face some discrimination in the greater multiverse, as a whole Tieflings in the planes have a better go of life than those on the Prime Material.
If one wants proof that Tieflings are not restricted by their parentage, one only needs look to Prima.
After the fall of Primus, the head of the modrons, one of the most lawful gods in the universe, it was a young tiefling who took up the mantle of his godhood and became the new leader and mother of the modrons. There are very few in the universe who could be lawful enough to take up the mantle of Primus and not have it immediately reject them outright. The fact that it was a tiefling, born of demons, the purest agents of chaos in the multiverse is astounding.
Some have tried to argue Orphei was born of the lawful Devils to explain this away, but testimony by her group and those who knew her before her ascension all attest to her Demonic heritage. Being involved in her quest, I know this to be true as well. Our mutual acquaintance and her fellow tiefling, Kylie frequently would shake her head at just how lawful Orphei could be, especially in comparison to her chaotic self.
It is of course still unknown what effect if any her demon blood could be having on the modrons because, of course, they have not yet begun their latest march and Prima has kept them mostly to Mechanus and visitors out as the plane restabilizes after the events of The Final Modron March.
—Estavon the Former Merchant,
An Insider's Guide to The Final Modron March.
Much rarer due to the more limited touch and presence of the lower planes, some tieflings do live in and are born in the prime material planes. They are often viewed with much mistrust, assumed to be a demon or like their devilish forefathers. Many are killed at birth for having their more obvious traits and those that are not are usually more subtle in their demonic and often try to keep that a secret to avoid persecution and murder.
Many tieflings were once sired for the purpose of fighting in the eternal blood war between demons and devils, thinking that it may turn the tide. Because of this, Tieflings must be careful when visiting the hells if they wish to avoid conscription. Nevertheless, some wish to know their hellish parent and will travel to find more about their past or because they feel they can better fit in there. Some are purposefully raised to fight in the blood war even by human parents involved in a demonic cult.
There are few tiefling societies, those that do exist are out in the planes, almost never on any prime material plane. Because of this, many on the material planes become nomadic if they are not able to easily fit into a society. This leads to them becoming adventurers and often makes them distrustful of others as mistreatment is very common.
Tieflings born to other races typically have names reflective of that culture. Those born to other Tieflings and those who take on a new name more reflective of their hellish identity have names derived from the Infernal language.
Male Names: Amenos, Amnon, Barakas, Damankos, Ekemon, Iados, Kairon, Leucis, Melech, Mordai, Morthos, Pelaios, Skamos, Therai.
Female Names: Orphei, Kylie, Akta, Anakis, Bryseis, Cirella, Damaia, Ea, Kallista, Lerissa, Makaira, Nemia, Orianna, Phelaia, Rieta.