Grove of Ash
Vazti, the Lord of Rage is a demonic entity trapped inside the Vazti Scroll. The Wandering Folk once worshiped Vazti as a god, as it enslaved their people through cultists using blood sacrifice (much like Akadi in the southern East), but the Dozen overthrow the cult, trapping Vazti in the scroll.
During the Ashen Shadow crisis of 881 RE, the high druid Scarno has stolen the scroll. In his fight with the Xindari, the essence of Vazti was released from the scroll, taunting them to pick it up and embrace their power.