This quest is not available in game.
Speak to Dark Ranger Velonara.
My people are not generally fond of the arcane arts that so many other races abuse. Thankfully the wizards within the Scarlet Monastery library are separated from us by considerable land, but their ability to transcend the physical realm concerns me and, ultimately, my tribe's survival.
Travel far to the west to the monastery's library and speak with Dark Ranger Velonara there. Her forces are already poised to strike at Arcanist Doan himself, head magi for the crusade.