The Well of Eternity

Ten thousand years before the events most Warcraft fiction covers, the night elf empire thrives around the Well of Eternity — until the ambitious Queen Azshara and her highborne magi, hungry for more power, open the world to the Burning Legion's invasion. Sent back through time to stop a catastrophe they know is coming, the dragon Krasus and the mage Rhonin ally with the young druids Malfurion and Illidan Stormrage in the opening book of Richard Knaak's War of the Ancients trilogy.