Beginner's Guide to Aasimar
A long time ago, the world of Toril was in trouble. The ravages of the spellplague took a catastrophic toll upon the population, making it difficult for the economy to function. A particularly-enterprising group of wizards sought to solve the problem by stealing people from other planes to use as slaves. These slaves cried out for deliverance, and their prayers were eventually delivered to the gods of their home plane.