After the creation of the permanent self-writing tome Klara Libri, the Celestial research group continued their experiments on Klaronium and as a result, they created a device that would forever continue to gather Holy Power.
The weapon was first used to end the First Demon War 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 Kounat troops and the goddesses to handle. Powered by the goddesses Ernasis, Lisnar and Amenias, the Aernas Hammer decimated nearly the entire demon infantry and severely injured their leader Heitaros Cratsus, forcing them to retreat.
The Aernas Hammer was used again by the Kounat kingdom's Prime Minister Baldinar. After he acquired the Klara Libri, Baldinar wanted to become the new Creator and sought power. He attempted to merge the Aernas Hammer, Soul Stone and the Demonic Essence to obtain the ultimate weapon and achieve his goal. Unfortunately, it was too late when he realized that the Soul Stone could only be controlled by the Kounat Royal Family who was the only ones capable of withstanding the "Geas" imposed on them by the gods and thus lost control of the weapon. By then, the Aernas Hammer was completely unstable and resulted in a gigantic explosion that consumed all of Kounat.
Despite the loss, Baldinar was not deterred from his goal. The person now known as Ashtaroth reforges the Soul Stone through the Deity Orbs and attempts to reacquire the Aernas Hammer. In addition to his goals, he plans to destroy Aernas with the weapon so he may rebuild it in his image.
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 but 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 Duel arrives in the nick of time to stop the weapon from completing. The Aernas Hammer then attempts to self-destruct once again but Grandiel then uses the Klara Libri to seal himself with Ashtaroth and the Aernas Hammer in the Wizard's Labyrinth for all eternity.
in Grand Chase Dimensional Chaser
- Oddly enough, the game never mentions the Soul Stone turning into the Aernas Hammer.
- In Kounat's Collapse, the Aernas Hammer warping Mari to it may suggest that the weapon is sentient.
- The Crown of Sands is very similar to the Aernas Hammer as both of them are powerful ancient artifacts that grant their wielders god-like powers and had been divided into fragments.
- Aernas Hammer has occasionally been misspelled as "aernasis hammer".
- In Grand Chase Dimensional Chaser, this becomes a recurring typo due to the poor translation.