2.1 Advanced Dungeons & Dragons 2nd edition.

In 4th Edition Dungeons & Dragons, tieflings are a race whose human ancestors made a bargain with devils to increase their power. This description remained true in 3rd Edition. In further supplements it was clarified that Tieflings were usually descended from fiends but not the same manner as half-fiends, since a Tiefling's fiendish ancestry lies further up the family tree. In the Planescape setting, where Tieflings were introduced, they were described as being a mixture of human and 'something else' with the implication that the medium-sized non-human ancestors originated from the evil 'lower planes'. Originally introduced in the Planescape campaign setting in the second edition of Advanced Dungeons & Dragons, they became one of the primary races available for player characters in the fourth edition of the game.

The tiefling ( / ˈ t i f l ɪ ŋ/ TEE-fling) is a fictional humanoid race in the Dungeons & Dragons ( D&D) fantasy roleplaying game. Fictional humanoid race in Dungeons & Dragons

5th edition playable races