It all starts with HBO's Carnivale. Several thousand years ago, the first avatara appeared: one an avatar of good, the other of evil. Every generation, two new avatars were born. The avatars were receiving their good/bad powers from either the white or the black lodge. Had Carnivale not been cancelled, Word of God is that it would have ended with the Trinity nuclear test, in the mid 1940s. It's also stated that Sofie is the Omega: the last of the Avatar, neither good nor evil, the one who will bring about the end. So, in the mid 40s, the avatar lines cease. The lodges, however, continue to exist.