In those days after the catastrophe, one figure was especially iconic: that of the lone traveller, often an older man who lived for a very long time and who was both skilled as a warrior and had a deep understanding of the energies.
In many cultures, this figure was known as the Constantine, or the constant one. He was a mysterious figure, and would show up generation after generation, seemingly never aging. There were many such men known in history, and they all trace back to the meddling of the Anu.
The Constantine would travel the world, carrying ancient knowledge and applying this knowledge in the world where needed.