Embron was a wizard's apprentice in Dalaran, hoping to one day become a great archmage of the Violet Citadel. One day he was tending the Dalaran-controlled farmlands of Ambermill when The Blackheart Templar entered the area. Embron, along with the other mages and farmhands of Ambermill sensed the corruption of the group and, not knowing their intentions, attacked them blindly. The Templar, being adept at battle, easily overcame their attackers, laying siege to the farm and killing several, including Embron, before the humans retreated to their magical city. It was at this time that the leader of the Templar, Mauron Alnamis, discovered his own innate ability to raise the dead and sway them to his will. The dead mages and farmhands then rose as undead minions, joining the Blackheart Templar. Mauron named his new undead servants The Dark Hand Covenant and set them on the path to paving the way for the Burning Legion's entrance into Azeroth.
Over time, Embron gained the trust of Mauron and was made second in command of the Dark Hand Covenant. He founded the Inner Circle, a group of powerful warlocks within the cult, who would be responsible for performing the various rituals that would summon demons into the world. They would turn out to be his most loyal and trustworthy minions.
After several years, the Scourge had become a prominent presence in the world, and Mauron took notice of this. He felt that the Dark Hand Covenant would better serve its purpose in accordance with the Scourge, since both factions shared the same goals. However, when he attempted to make contact and merge with the Scourge, Embron took action and betrayed Mauron before he could do so. He cast a spell that tore Mauron's soul from his body and imprisoned it within the bounds of his own personal grimoire, which he magically sealed, forever banishing Mauron. Embron then took control of both the Blackheart Templar and the Dark Hand Covenant, maintaining independence from the Scourge and altering the cult's goals to his own ends.
Eventually, several members of the cult began to develop their own independence, since they were no longer controlled by the power of Mauron's will. These self-aware members, led by Dalan, Banisher, and Krall, sparked a revolution that ended in a magical battle among the cult's mages. Banisher challenged Embron, and after a magical duel, collapsed the cavern in which the battle took place, killing several cultists, including Embron, and putting the survivors into a mystical hibernation.