This quest is not available in game.
Travel to Darkwhisper Gorge in Winterspring and recover 5 Tears of the Hederine from the Hederine demons that occupy the gorge. Return to Daio in the Tainted Scar when you have completed this task.
The Hederine demons that occupy the foothills of Mount Hyjal secrete powerful fel poisons, which if left to mature, harden into a dense anti-magic crystal. These crystals have come to be known as Tears of the Hederine.
Not even the immense power of a Doomguard could break the walls of a prison constructed from this material.
Travel to Darkwhisper Gorge in Winterspring and recover the Tears.