Tieflings

Tieflings are strange fiendish individuals who are rumored to hail from The Fargone City and have a strange connection with Sphinxes, who are also rumored to hail from the Fargone City.
All of the tieflings who have arrived within the Material Plane, Hetarunde, itself, have had no memory of their lives before arriving, which has led many to believe that Tieflings are a race punished by their former comrades, cursed with a fiend-like visage and the loss of their memory. Other philosophize that they were part of a cult or underwent a vile transformation of their own accord to develop the visage and fiendish powers, and their punishment consisted solely of their banishment and erasure of memory.
Although not all tieflings are evil, many of them end up there. They fall under scrutiny by most other races and have definitely suffered from prejudices and otherwise in the past. Most tieflings also have some sort of quirk or behavior that firmly betrays them as otherworldly. This trait can be something like sleeping with their eyes open, sleeping standing up, a fiendish birthmark, the inability to blink, a constant expression of writhing agony when unconscious or absentminded, or something similar.

Tieflings as a Playable Race

Tieflings in play are identical to the version within the Player's Handbook, with the following abilities:
Fargone Sense: You naturally sense the presence of any Sphinx within 1 mile of you, although you can not discern its location. While sensing the other and within 120 feet, you can speak telepathically with it. You ignore a Sphinx's immunity to the frightened condition.
Infernal Legacy: Some Tieflings draw more on their connection to The Fargone City and Meralyst than their connection to the lower planes and fiends. You may choose to replace both Hellish Rebuke and Darkness from your Infernal Legacy trait with a once per day use of Misty Step (once per day at 3rd level, and twice per day at 5th level), as the Tiefling adventurer learns to manipulate the Fargone City and reflections to teleport.
Names: Tieflings, like Half-Elves, are a traveling race that doesn't have much of a place in the world, and their naming conventions reflect this. Tieflings often will name themselves names that reflect the cultures within which they reside, with a general preference towards halfling and elf names. They only really adopt traditional tiefling names when in isolated Tiefling communities.