Scars of Faerûn
Mystra, the Mother of all Magic, was a greater deity and the second incarnation of the goddess of magic, after her predecessor Mystryl sacrificed herself to protect the Weave from Karsus’s Folly (Karsus was the creator of the Netherese nation and line of wizards. He created a spell to steal the power of Gods and bestow it to himself. He tried to steal the sceptre of Mystryl).
Mystra’s assassination kickstarted the Spellplague.