The Wheel of Chaos was a terrible artifact, the true source of the devastation during the Planar Wars. It took thirteen Soul Mages to forge, using the excretions of thousands of dying souls, the substance known casually as chaos cheese. Those in charge of the Wheel were renegade members of Tempest, who were acting without the knowledge of the rest of the faction. The Wheel's effects seemed benign at first, allowing great power to those who touched it. It took many years for its true effects to become apparant, by which point it was too late. The Wheel slowly ripped apart reality, but as it grew in power, and more souls were added to it, it twisted reality ever faster.
In 4700, Suzcecoz soulfired the thirteen Soul Mages, but Rhuan escaped. She called in Keolah, who broke the Wheel using the Zarnith, and gave the pieces to people to spread the power of the Wheel. It was so much power being in one place that caused the chaos.