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.
Atlantica Online charges players with culling together a party of NPC mercenaries that they lead across the world, a fantasy/steampunk-laden alternate version of our own Earth. All battles are turn-based, with each side (your party and the group of enemies) taking turns in combat. Both the main character and your NPC party members gain experience, gaining access to additional equipment and new skills, as well as opening the door for progressing to an advanced class.
Atlantica offers a wide variety of content for all types of players. There is content geared towards PvP with many tournaments that routinely open up that are easy to join in, as well as many quest-filled dungeons that can be run both alone and with other players' parties for the more difficult of bosses.
Official website: http://atlantica.ndoorsgames.com/center/default.asp