In the setting of Dungeons & Dragons 4th Edition, the tieflings trace their origins to the ancient human Empire of Bael Turath. In the Empire, the noble class was completely obsessed with preserving and gaining power. Rumors of their schemes and obsession with power reached a realm called the Nine Hells, located around the Astral Sea. The devils that resided in the Nine Hells gave the ruling classes of Bael Turath visions while they slept, containing the directions for a grisly, month-long ritual that would extend their rule into eternity. The details of the ritual have been left unclear in the books from the Player's Handbook series describing the events, though it is described as being very horrible. As the ritual demanded the participation of every noble house, those that refused were wholly slaughtered. Once this was done, the ruling class began their ritual. Afterwards, devils from the Nine Hells began to appear, and the nobles gladly made pacts with them. These pacts gave power to the nobles and their descendants forever, but also gave them the devilish features of horns, non-prehensile tails, sharp teeth, and red skin. From that point forward, the former humans were the race known as the tieflings.
