Campaign Introduction: You have received the opportunity to travel to Grex, the new frontier, and have decided to take the chance to travel to a new land, rumored to be vast and untamed. The only way in, other than an impossible climb through the mountains is through the newly constructed Underpass, an impressive feat of dwarven, human, and Gnomish engineering cutting straight through the mountain for tens of miles. The Kallonian Empire has technically declared Grex a new province, but in practice Grex is a free and mostly lawless land. You are a member of the early settlers, guaranteed ownership of any land and property that you are in possession of after one year, at which point a new group of settlers will be sent. A land of opportunity and adventure awaits.
Present Day: The Heroes of Greywater Keep, when they defeated Priam and destroyed the Maw, caused a ripple effect through the cosmos and Aenor. Great earthquakes shattered walls and toppled Mountains. Seas overflowed and land rose from the sea. The sky went dark for a time, and only after some months did the world finally calm itself. When the dust settled and the peoples of Aenor began to take stock of things, a number of changes became more and more apparent. This event has come to be known as the Rivening
It became apparent to those interested in such things that the Gods have but a very tenuous touch upon the world and a limited ability to impact the world. Where they have gone is not known, but their power no longer fills clerics with great power, and their effect upon the world has lessened to a mere trickle or power.
This reality does not stop the faithful from believing that they still watch over. Even when the gods were accessible, the normal folk of the world had limited interaction, and so the change was barely noticeable. Because of this, especially where the Churches maintained influence, the gods are still worshipped and revered and their followers await their return, or seek to expedite the return.
The demise of Tsothogga had another impact upon the world, as drastic and impactful as the minimizing of the Gods. His tendrils had snaked into the Leylines of the world, those lines of magical power that gave birth to and ability to Arcane magic users, and when he was cut from Aenor by the heroes, his tendrils calcified, and destroyed many of the leylines, but created the mineral now known as Darksteel, or Tsothite. Where his tendrils were not, some of the leylines, deprived of their connection to the energy bringing Cosmic energy also calcified, turning in to Truesteel, or Arcanite.
With the loss of the so called “Immaterial Magic”, full casters were severely limited or lost their power, where before it was nearly limitless with enough time and study and innate talent. Now, it is dangerous and unstable. This led to a boom in the “Material Magical Sciences” those of Alchemy, Blacksmithing, Artificing and Engineering. The gnomes, who had already been so inclined were some of the frontrunners of these disciplines. The world still contained a great deal of inherent and imbued magic in the materials of the world and gave ample opportunity for the inventive.
Another strange and inexplicable change took place with magic. That magic which relied upon music and song seemed to remain unchanged. Suddenly, Bards and Skalds, those who bolstered their companions and altered the world with song seemed unaffected by the destruction of other kinds of Magic. Scholars, musicians, and alchemists have attempted to figure the reason behind this, but have been unsuccessful. This has led to the creation of the Philahrmonic.
With much magic lost, and the Gods now absent, the power of the common man and his ingenuity has never been more important.
Take a look at the wiki. There is fluff about the world of Aenor there.