Flawless Arcane Essence

This item is one of the objectives of the the quest The Soul Cannon of Reth'hedron, which begins with Illidari Lord Balthas in Dragonmaw Base Camp in Shadowmoon Valley. To complete this quest, players must speak with Sar'this at Lake Jorune above Stonebreaker Hold in Terokkar Forest and kill the five elementals he summons.

As a quest objective

 * The Soul Cannon of Reth'hedron