It was Wizard King Maelezar Grimwind that attempted to control an event known as The Planar Convergence, and use its power for his own gain. In a ploy for immortality Maelezar unwittingly unsealed a long forgotten plane – The Writhing Chaos. It was the opening of this realm that created a magical surge throughout the Leylines causing them to rupture. This rupture consequently created rifts in the material plane to all other planes and tore the pantheon from their seat of power.
If was this event that released the terrible evil that was sealed within The Writing Chaos – The Demon-King Azemoth. Stepping forth from his eons long imprisonment, his mere presence rippled through the planes, alerting the Over-Diety Uthon.