The Earthen Ring quartermaster is a vendor found in one of the first zones you can visit in World of Warcraft: Cataclysm. As the name suggests, they're tied to the Earthen Ring faction and sell a variety of goodies to those who have earned sufficient reputation levels to unlock them.
Daily quests play a big role in Cataclysm's endgame, and allow you to raise your reputation level with the faction residing in each area. Earthen Ring is found in Vashj'ir, for example, so you'll need to make your way to that underwater zone if you want to complete the quests and track down its vendor.
