- Ultimate Mortal Kombat 3: "An enigma to all who come into contact with him. Ermac's past remains shrouded in mystery. It's believed that he exists as a life force brought together by the souls of extinguished Outworld warriors. Shao Kahn has managed to take possession of these souls and use them to fight on the side of tyranny."
- Mortal Kombat: Deception: "We are Ermac. We are the fusion of the souls of dead warriors, created by Shao Kahn to obey him without question. We served as his enforcer for many years, until the Earthrealm warrior Kenshi released us from our bondage and awakened our perception of the worlds that surround us. We are now free to choose our own destiny. We encountered a fellow warrior spirit who, like Kenshi, understood our suffering. Eager to atone for the atrocities we had committed in Shao Kahn's name, we agreed to help this warrior, Liu Kang, to liberate his allies from the control of the Dragon King. Shao Kahn may be dead, but it seems his essence lives on in this new menace. It is as if they are both manipulated by the very fabric of the realms."
- Armageddon Bio Kard: "The enigmatic Ermac is a being composed of the souls of conquered Outworld warriors. For many years he served at the side of Shao Kahn, but has since freed himself from the emperor's influence. Once a force of evil, he now controls his own destiny."
Ermac was one of Shao Kahn's deadliest warriors. He was created by the emperor himself, through a fusion of souls. Ermac carried out missions for the emperor and in one of his missions in the Netherrealm, Ermac became acquainted with Shujinko, an Earthrealm warrior that roamed the realms on a quest to find the ancient Kamidogu. Ermac taught Shujinko his own abilities in return for the help Shujinko gave him. Ermac was in the Netherrealm to slay a demon, but the Netherrealm drained Ermac's power and only the Soul Stone could stop this process. Shujinko found and brought the stone to Ermac who thanked him for his help and offered himself to train Shujinko. Later on, Ermac was assaulted by Ashrah who believed him to be a demon, but he parried her attack easily.
Ermac participated in the invasion of Earthrealm. However, after Shao Kahn's defeat and subsequent loss of power, Ermac remained under Kahn's control and wandered Outworld without instructions. During the events of Mortal Kombat: Deadly Alliance, the wandering Ermac was found by the blind swordsman Kenshi and was freed from Kahn's control. To show his gratitude, Ermac taught Kenshi the "Telekinetic Slam" technique.
Ermac's new found freedom meant he was also free to choose his own destiny. He decided to repent his earlier ways and became a force for good. After making this decision, he met a warrior soul who, like Kenshi, understood his suffering. This warrior soul was that of Liu Kang and was not only in need of another ally, but assistance in freeing his enslaved comrades.
Ermac was eager to help Liu Kang, as this was an opportunity to help him atone for the evil he had committed in Shao Kahn's name. Ermac decided to help Kang and the two would set out to free the Mortal Kombat champion's allies (Jax Briggs, Johnny Cage, Sonya Blade, Kitana, and Kung Lao) from Onaga's control. They are eventually successful in their pursuit.
Later on, Ermac joined the Forces of Light in the battle of Armageddon, where he swiftly incapacitated if not killed Rain when the battle began. However, during the battle, he disappeared for a short time, allowing Shang Tsung to take his place. Ermac was later shown to be among those who eventually died.
- Ultimate Mortal Kombat 3: "Having been in hiding since the first Mortal Kombat, neither the Earth nor the Outworld warriors has recognized this elusive ninja. Ermac uses his victory in the tournament to prove his existence... As well as a warning that he will return as an unstoppable force in the fourth Mortal Kombat."
- Mortal Kombat Trilogy: "When Kahn finally eliminates his opposition, he finds a new and surprising foe in Ermac. The Outworld souls that give life to the warrior did not trust their tyrannical leader who planned to consume the powerful life force of his own power. Even Shao Kahn's power was no match for the over-whelming strength of legions of deceased Outworld warriors. They destroyed their master in a battle that devastated the entire realm. Ermac was left behind to rule it with his own brand of oppression."
- Deception: "In an outer chamber of the Dragon King's throne room, Ermac did battle with Liu Kang's enslaved comrades. Ermac was more than a match for the five warriors, but their defeat was not his objective. Liu Kang materialized and, one by one, freed their souls while Ermac occupied the rest. Eventually, all five were awakened from their enchantment and freed from Onaga's control. Ermac was pleased that his warrior skills could for once bring about a noble outcome. He sensed, however, that an ominous force still shaped the destiny of the realms. It was everywhere. He could feel its influence on Onaga, though the Dragon King was oblivious to its manipulation. Time was running out. Ermac feared the celebration of this latest victory would be short-lived."
- Armageddon: "The energy of Blaze shattered Ermac, separating him into the many warriors who comprised his being. Now each with his own physical form, the Ermacs are linked psychically and act according to their collective consciousness. No longer a mere fusion of warrior souls, Ermac has become an army."