You'll have to fight your way deep into Sebilis. Mobs are 84^^^ to 85^^^ and they can cast a noxious ST fear spell.
Harvest a Sathirian Blood Vase ( -75, -125, 520 ) Copy/waypoint -75, -125, 520 in Venril Sathir's Hall. This is on the same level as the Reet Slave Mines from the quest before, on the left side of the corridor leading to Venril Sathir's lair, a raid zone.