Excavation of the ruins left by the Ymirus was more than a display of reverence toward the gods of the distant past—it was an expression of human ambition in the present. Four hundred years ago, Drave the Snake-Eyed discovered Arche ruins, marking the beginning of the use of blue crystal energy and Archecores. The combination of the two brought fresh hope to human civilization.

Each Archecore served as an engine of godlike power. Fueled by refined blue crystal, they powered kinepolises, which enabled even more efficient energy extraction and excavation of ancient technology. The dramatic expansion of human activities resulted in encounters with gigantic chimeras, the like of which had never been seen before. These chimeras moved freely through areas polluted with blue mist, eating contaminated plants and other animals.
A number of weapons were developed based on runic diagrams preserved in crystal found in the Arche ruins, including gunpowder weaponry, which was either manned by a large crew or installed on kinepolises to defend against chimeras. But these weapons were limited to reactive, defensive, or suppressive uses. Meanwhile, human infantry equipped with crystal armor (Arche Knights) also powered their equipment with blue crystal Y-thermoses. Their heavy armor and weaponry used blue crystal steam power, channeled through piping embedded in their armor. But these were inadequate to challenge the chimeras. Attacking them required a whole squad working together, and was often a matter of enormous cost for little gain.
Furthermore, the chimeras had the mysterious ability of chimerism—they could assimilate and evolve all sorts of incredible biological functions, including an organ called the xenoluce that carried out energy conversion.
Humanity soon discovered that the chimeras also drew their strength from blue crystal energy. Drawing inspiration from myths about the Ymirus, scholars concluded that legendary weapons capable of directly using blue crystal energy were needed in order to drive back the chimeras.

The rulers of the Eight Kingdoms ordered the continued excavation of the Arche ruins. In addition to the rare all-purpose engines powered by blue crystal energy that became known as Archecores, giant skeletons made in the image of the Ymirus were also discovered. These were dubbed Ymirus mech frames.
As legend would have it, these giant warriors fought side-by-side with the Ymirus during their civil war. Now, they became humanity's hope.
The Archetechnologist Dr. Ascart discovered the secret of the Ymirus mech frames: if implanted with an Archecore and injected with blue crystal energy, they would come back to life. It seemed that the Ymirus shared a genetic code with humans; as a result, it was possible to pair the reconstructed Arche-Ymirus mechs with distant descendants of the Ancient God who carried the blood of their ancient controllers, and create a link between them.

Under the control of the theonavs (known outside Veck as the soulbound), the Arche-Ymirus mechs in all their might walked again.
Thus did the Arche-Ymirus mechs of legend reawaken in the modern world as weapons of the state.