I'm new to the franchise and must admit that how the tieflings are presented is passing strange to me? I mean just as soon as you visit the druid grove they all seem like the most normal and sweet people that one could ever meet and yet they all stem from within the Seven Hells??
In fact, tieflings are ordinary people. Their specific appearance is due to the fact that their ancestors were somehow influenced by fiends. Perhaps their ancestor was a warlock who took an oath to one of the fiends, maybe he was a Cambion, maybe they were subjected to planar influence in the mother womb... There are many options. In any case, a drop of fiends' blood does not make them evil. And, one more thing, Nine Hells. And since we are talking about Nine Hells, not all of tieflings come from baatezu. The ancestor of the tiefling can also be the yugoloth, tanar'ri, and more specific types of fiends. In the 3rd edition, tieflings were mentioned, descended from night hags. This is continues in Pathfinder, where tieflings can come from all fiends, even from qlippoth, strange fiends similar to Lovecraft monsters.
