He was a member of the Infinite Dragonflight, a race of evil, time-travelling dragons bent on destroying the world via changing major events in history. The Epoch Hunter was tasked to ensure that the Orc, Thrall, never escapes from slavery, resulting in the Horde never being rebuilt and the Legion having one less obstacle in their conquest of Azeroth. Unfortunately, the Epoch Hunter was challenged by a group of adventurers sent back in time by the Bronze Dragonflight, a race of dragons who work to keep history intact.
The Epoch Hunter did everything he could to complete his mission, and even kidnapped Thrall's best friend, the human woman Taretha. The Epoch Hunter imprisoned her within her own bedroom, and while Thrall and the heroes were discussing what has happened, the evil dragon called the escaped Orc and his allies outside for a final battle.
Thrall and the heroes heard the call, and saw the dragon flying above the small town of Tarren Mill. With the aid of the Infinite Dragonflight, the Epoch Hunter outnumbered the heroes greatly, but after loosing his patience and his army, he descended to the ground to battle the heroes himself. He was overwhelmed, and was killed within a couple minutes. The heroes were successful, and the spies of the Bronze Dragonflight warped the memories of Thrall and Taretha so that they would remember that moment as the original timeline.