The birth of all things

In the beginning there was a single entity, alone in a void. After a while, the solitude became overwhelming and he decided to create another being. This second being was a deeply passionate and joyful individual, and she in turn began creating life; those who would be known as the first men and women. The First became deeply envious of both The Second and the humans; as he was yet to experience anything resembling joy or happiness. Eventually - this depression seeming to be endless - he lashed out at the humans, deciding to take their lives in anger and jealousy. So began a lengthy fight between The First and The Second. Now far beyond the point of no return, the First began to cast Curses, and the Second in turn cast Blessings.
Now, Blessings and Curses are the most powerful magic in the world; but they come at a cost. To alter the world on such a large scale, they used up their own essence eventually disappearing entirely.
The first Curse was as such: None shall escape death The Blessing that followed was like it: None shall remain dead
The next curse was uttered: Monsters shall wonder the earth in pursuit of causing suffering for humans
This continued for some time, and eventually there was nothing left of these gods. And the humans were left to fend for themselves.

Historical Basis

For the most part this tale is accurate, though the wording of the Blessings and Curses have been distorted over time, and a lot of the minutia has been lost to time.