Atlantica Online : Plot
Atlantians became very prosperous after they created the substance called Oriharukon. Wanting to learn the secrets of this mysterious material, many other civilizations implored the Atlantians to share their knowledge, but they refused, closing their door to outsiders. Anyone that persisted, the Atlantians brutally destroyed.
Eventually, the Atlantians exhausted all the supplies of the four crystals, the raw materials for Oriharukon. Their thirst for the crystals led to the destruction of four great civilizations (the Yellow River, the Indus Valley, Mesopotamia, and Egypt), and set them on a path to conquer the world to find more.
But the arrogance and greed of Atlantians would instead lead to their demise. When they lost control of the magic powers generated by Oriharukon, Atlantis disappeared in the blink of an eye. But, remnants of Oriharukon survived.