Note: If you hear fighting inside the restaurant (ie. another person/group already fighting her), wait outside until the combatants exit, otherwise it seems to bug the encounter and she will not spawn for you.
Return to Aaronolis and report your findings. Isabell's suspicious comments point towards the involvement of Innoruuk, so you must find where his followers are hiding in Greater Faydark.
Travel to the The Combine Spires and find the altar of Innoruuk. (The altar is located near the lower leg of the spire, where all the spiders are.) Nearby is a suspicious gem ( -505, 45, 272 ) /waypoint -505, 45, 272. Collect the gem and return to Aaronolis.
The priest sends you to seek out Farra Marthen, a Sister of Peace just past Silver Leaf Inn ( 324, 92, 335 ) /waypoint 324, 92, 335, to see if a follower of Quellious the Tranquil can quench the hate in the stone.
Farra gives you a Blessed Crate of Tranquility. You must collect 12 malefic quartz and place them in this crate to neutralize its emanations of hatred. These appear as small heaps of dirt randomly located on the forest floor. The talk page lists confirmed locations with waypoints, but in general, they appear:
around the Green Knoll ( 429, 52, 74 ) /waypoint 429, 52, 74
in and around the Druid Ring ( 217, 13, 2 ) /waypoint 217, 13, 2