摘抄自WIKI
In 1358 DR, a warlock coven known as the Toril thirteen performed a ritual that cursed most tiefling lineages—those of demons, devils, hags, and rakshasas, among others—with the "blood of Asmodeus", changing their original lineage with that of the archdevil himself. This was done to make Asmodeus a "racial god", ensuring him enough followers to attain godly powers.[17]（Erin M. Evans (October 4th, 2016). The Devil You Know这是官方小说. (Wizards of the Coast), pp. 262–264. ISBN 978-0786965946.）
合着这个说法是后面补票增加设定说服力的，而不是顺着时间线写的。
After the Spellplague of 1385 DR, when Asmodeus became a god, the magic of the ritual took effect across all of Toril and afterwards most tieflings living in the 15th century DR were of the Asmodean lineage, all having a similar devilish appearance.[18]（Steve Kenson, et al. (November 2015). Sword Coast Adventurer's Guide 是SCAG不用多说了. Edited by Kim Mohan. (Wizards of the Coast), p. 118. ISBN 978-0-7869-6580-9.）
