Ervin wants to drive all the Balaur from Brusthonin, including the dead ones. Go kill undead Balaur in the Wailing Cliffs.
Step 1.Go to the Wailing Cliffs and kill Undead Balaur.
Step 2.Talk with ErvinBaltasar’s protector in Baltasar Hill Village. She ascended after the Balaur killed everyone else in her village. She has a strange connection with the holy tree..