Celestial
The first divergence was a time when man first got their magic from the gods. they were given the power to defend themselves against threats developing in the realm. demons and devils hard worked the way in after being created by the old gods to try set things right. when the world was invaded by these demons the gods fought back defending their creation to the last. a lot of the gods were killed or forced into hiding, one was left behind as a hero, however. The goddess Mystra rose up against the hord or demons and created a vail between all realms separating the mortal world from the others such as the nine hells.