Corruption of Earth and Seed

In the depths of Maraudon lives a creature of chaos and evil, $N. Princess Theradras is an elemental force of earth related somehow to the Old Gods. Ages ago, she was sought out by Zaetar, first son of Cenarius. The offspring of their... relationship are the creatures known as centaur. Ever-thankful creatures, the centaur killed Zaetar, and now Theradras keeps his remains. My quest here is to find those powerful enough to slay Theradras so we may recover Zaetar's remains before returning to Stonetalon.