Thang Online is a free-to-play fantasy MMORPG from Jaca Entertainment. The storyline concerns a growing evil that has been prophesied to occur and destroy the land. It's an action-oriented game with featured leveling, Monster and Ki Transformation systems, player-crafted and enhanced armor, and more.

On the eastern end of the continent called Om Lit Praga, whose history is more ancient that anyone can ever imagine, gods and men still live in harmony, and numbers of tribes live peacefully, enjoying the rich gifts of green forests and meadows from the Mother Nature. These tribes had one common legend, passed on for generations: the legend about a god named On-Du.

One day, the crevice of Mana the Moon will be opened, the eyes of On-Du will be blinded, and the ghoulish howling of beasts will echo across the sacred Rvai Mountains which no one ever attempted to climb. One day, all the gods of nature, even the gods of Sun and Wind, will shudder in terror. Old forests and vast plains, which the tribes depended their lives on, will lose vitality according to the legend. This terrible legend warns that beasts and even domestic animals will go mad and the world will grieve at the terror and pain.

The wave of this legend now begins to sweep across another civilization in the western territory of Om Lit Praga, beyond the Rvai Mountains. This civilization, called Aguda, is separated into two: Light and Darkness, and these two have been at war for hundreds of years. However, Darkness is defeated, and its power begins to approach the holy Rvai Mountains. People of Darkness wield black magic and worship darkness, destruction, and curse blindly, and they are trying to prey on the peace of On-Du in order to build power needed to challenge Light once again.

There is always hope, however, even in despair. The hope will flare up - young, determined warriors from each tribe. They are the ones who will fight the doom with dedication and passion. They are the chosen ones who will climb the sacred Rvai Mountains that never allowed any other's footsteps, and they are the ones who receive the spirit of Thang the Phoenix God of the Rvai in their hearts. The Seal of Thang will be opened, and the young warriors, the incarnations of Thang, will tackle each and every disaster ahead of them. Their legend begins now.