Glyph of Purification



The Glyph of Purification was created by ancient druids. The glyph had the power to heal the land and was held by the Khan of the Stonetalon centaurs. Thrall and Cairne Bloodhoof killed the centaur khan and his tribe in order to get the glyph and purify the Defiled Fountain.

Source
Thrall and Cairne Bloodhoof find this in Where Wyverns Dare, chapter 6 of the Warcraft III orc campaign, The Invasion of Kalimdor.