Creation.

The spirit of the beginning, consumed the nothing. This did not fill it.
After consuming all of nothing, it consumed itself, crushing everything to the creation.
Creation began, forcing tears that created the realms and dimensions, overlapping and copying itself over and over, creating new mirror worlds following similar but different rules.
Races formed from what were the parts of the spirit, and the collision of planes warped and twisted the growth and development of the Taith, the collective races of creation.

Summary

The spirit was the beginning and the creation of everything, and the basis of creation. Everything is the spirit and everything comes from it. It is known by many different people that fragments of the spirit take form to name themselves and to rule and order aspects of the world, and keep balance between the planes.
Each religion known in the world is based upon the fragments of spirit exerting their powers in different ways which gain power with more believers but due to the chaotic faith some give, can in many cases accept worship of multiple fragments, but will also derive power from actions relating to their subject.

Historical Basis

Numerous worshippers who become enlightened to later on pass on the messages of different fragments of creation.

Spread

The creation of existence is communicated between every being. Albeit worshipped differently and told in many ways, all point to a universal creation.

Variations & Mutation

The original myth is renewed actively by the different fragments of the spirit, changing it to suit their doctrines in the favour of each fragment.