The weapon was first used to end the First Demon Wars, which took place countless generations ago. It was ultimately used as a last resort when the demonic forces of Elyos proved too much for the Kounatians and the Goddesses to handle. Powered by the Goddesses Ernasis, Lisnar and Amenias, the Hammer decimated nearly the entire demon infantry and severely injured their leader and forcing them to retreat, giving the Kounatians victory. However, the Goddesses were greatly drained by the battle and the weapon and were forced to retire.
The Aernas Hammer was used again by the Kounatian Prime Minister Baldinar, now known as Ashtaroth. 600 years prior, Baldinar acquired the Klara Libri, a legendary tome that contained all of Aernas' secrets, including its Creator. Driven by ambition, he wanted to become the new Creator and sought power. Baldinar acquired the Hammer, the Soul Stone, and Demonic Essence, and planned to merge them all to obtain the ultimate weapon to achieve his goal. Unfortunately, Baldinar realized too late that the Soul Stone could only be controlled by the Kounat Royal Family, the only ones who were able to withstand the Geas imposed on them by the gods, and as thus lost control of the weapon. By then, the Hammer was completely unstable and resulted a gigantic explosion that consumed all of Kounat. This event also had inadvertently created the Dwarf-Elf War on the Archimedia Continent, as the explosion killed both their kings; both sides blamed each other for the incident and have been fighting each other ever since.
Despite the loss, Ashtaroth was not deterred from his goal. In present day, he reforges the Soul Stone through the Deity Orbs and attempts to reacquire the Aernas Hammer. In addition to his goals, Ashtaroth plans to destroy all of Aernas so he may rebuild it in his own image.
In Kounat's Collapse, Ashtaroth succeeds in rebuilding the Aernas Hammer and uses its power to strengthen his human form as well as transform into a demon and a god. However, because the weapon lacks the key, Ashtaroth succumbs to the combined power of the Grand Chase and the Klara Libri's clone used by Kassias Grandiel. However, the Aernas Hammer suddenly warps its key, Mari, to the field, but Void arrives in the nick of time to stop the weapon from completing. The Hammer then attempts to self-destruct once again, but Grandiel then uses the Klara Libri and sacrifices himself by sealing himself, Ashtaroth, and the Aernas Hammer in the Wizard's Labyrinth for all eternity.
- Strangely, in-game never mentions the Soul Stone turning into the Aernas Hammer.
- The Aernas Hammer warping Mari to it in Kounat's Collapse may suggest that the weapon is sentient.
- The Crown of Sands is very similar to the Aernas Hammer.
- Both are ancient powerful artifacts.
- Both are divided into fragments. The Aernas Hammer requires the Soul Stone which is formed out of all the Deity Orbs; the Crown of Sands is split into three pieces.
- Both grant their wielders god-like power.
- In a final battle, both the item and their wielders vanish. Ashtaroth and the Aernas Hammer are sealed by Kassias Grandiel; Barakhufu and the Crown of Sands are destroyed.