Masters of the Universe
Lore, passed down through generations, tells of the creation of the Realm. Bards sing of the tale and historians record the stories in writing. It is said that the primordials entered the void at the dawn of time and forged the world from Elemental Chaos bringing about the natural order. Discovering this creation, the gods entered into the Realm and called sentient life move upon its surface. Soon after, the primordials and gods began to war. The war raged on for hundreds of years, almost bringing the entire Realm to destruction. Seeing that the very thing they were fighting over was about to be laid to waste, they made a truce and agreed to leave the Realm in material form, becoming observers from afar.
Two thousand years after the truce, the mage god known as Arcus snuck into the Realm and gave the knowledge of magic to men and they became the first wizards. At first, the wizards worshiped Arcus, but over the next thousand years they became arrogant and inward-focused as they uncovered the knowledge that they could study magic independent from needing to worship Arcus. The wizards formed the Gnostic Order and retreated to icelands of the north to refine their skills. In the north, the magi created an army of Warforged soldiers and laid siege to the Realm. As they came close to total domination of the Realm, the Order then turned their sights on replacing the divine gods. The ensuing war became known as the Realmbreaker War. When the members of the Order returned to their strongholds to defend them, the divine gods called a cataclysm down upon the Gnostic concentration of power in the north. As the Gnostic towers fell, the arcane backlash destroyed Arcus and the ceiling of the Realm was split causing untamed magic to be spread throughout the world.
It is two thousand years since the Realmbreaker. New civilizations have sprung from the ashes of old. Magic has begun to be studied again by a few who believe they can handle its secrets. Treasure awaits those brave enough to venture in to the fallen lands, and death awaits the foolhardy.
The campaign story log begins here.
There is some more helpful info on the wiki.