From the Art Book that came with the Limited Edition:
The cataclysm resulted in the near-complete destruction of the Kojan continent. Untold thousands perished as the land split apart and sank beneath the sea. Those fortunate enough to survive the initial destruction found themselves isolated on the islands of the newly created Kojani Archipelago.
The terraced human village of Tanvu remained virtually intact, as did the orc capital Martok. The wood elves and raki who survived sought refuge in the tree city Ca'ial Brael.
The years following the cataclysm proved a struggle for survival. Aftershocks and tsunamis struck down the strong, while famine and disease claimed the weak. Adversity forced the formerly antagonistic Kojani races to cooperate for survival. They learned to live off the land and the sea's fringes, or they perished. They opened exchange routes between the islands so each civilization could trade for what it lacked, even if that meant trading with the fierce goblins and orcs. With this new growth came the realization that the islands' limited resources would soon be exhausted. The Kojani peoples began to look toward the sea.
For hundreds of years, the Kojani races refined their boat crafting and navigation skills. Explorers sought new trade routes on the high seas, and they soon discovered Qalia and Thestra. The orcs and goblins immediately armed themselves to colonize Thestra by force. The humans and wood elves instead sought peaceful diplomatic relationships with Thestra.
Now, the races of the Kojani Archipelago travel the world searching for fame and riches as mercenaries, explorers and sages.