In the Dawn Era, the arch-angels and gods sought to build areas of stability and law from the raw energies of Chaos. This was not something that the primordials thought to highly of, so these chaotic beings took every measure to tear these divine creations apart, and return them to the heart of chaos.
On a world called Kriav, a cadre of arch-angels forged a magical device to be used as a weapon against any primordial incursions. The device they made has come to be known as a Cube of Arcane. The one on Kriav, was the first of its kind.
After several hundred years, Kriav's Cube of Infinity imploded, giving rise to the Cube Collapse. The magic that spilled out of it forever changed Kriav and the plane around it. The Feywild and Kriav were seen as a reflection of the Elemental Chaos rather than a place of stability and order. The divine powers, for a time, abandoned the realm and went on to create another - the Prime Material Plane.
