Allatou ancient past is a mystery that has gone unsolved for eons. However, she did hold a menial position within Satan's court. She was very ambitious and sought to increase her position, to do so she would seek more power. Her quest for power led her to possess the young girl Mary Manners, after her upset and disappointed father slapped her for having relations with a man he believed undeserving of his daughter's affection. The possessed young girl's retaliation caught the attention of the Son of Satan, Daimon Hellstorm. During her confrontation with Hellstorm Allatou rapidly jump from the bodies of Mary and her parents allowing her to escape.
Allatou remained in hiding for several years, however, she resurfaced on the earthly plane in the guise of the Grimoire Book Shop, owner Mr. Carstairs, who was now under her power. Allatou would soon fall into conflict with Master Pandemonium, who was believed to be searching for his lost soul fragments. While looking to acquire knowledge of the occult as a way of devising a plan to defeat Master Pandemonium, Dr. Henry Pym also happened upon the the Grimoire Book Shop. The evil Allatou overheard Pym while he was performing his investigation and thought him to be an agent of Master Pandemonium. She followed Pym back to the Avengers' Compound. At the Compound Allatou summoned a horde of demon servants to capture Pym, her actions caught the attentions of the demon Azmodeus, who then join the battle. By this time the West Coast Avengers had came to Pym's aid, but their interference proved to be meaningless, because Allatou capture Pym and Tigra.
The Avengers sought aid from Hellstorm and Hellcat, who were retired heroes at the time, having set up an occult investigations business. Together, the heroes invade Allatou's realm with Pandemonium on their heels. A three-way fight breaks out until Allatou manages to strand everyone with Pandemonium aboard a slab of stone floating through the various realms of Hell.
* Note: Allatou is not to be confused with the the Mesopotamian death goddess Ereshkigal, although it is suspected that Ereshkigal maintained her prominence and avoided demon degeneration by either expelling her demonic aspects as Allatou or by trading her husband and Babylonian name to the demon.