The First War

The Descendants knew that, with forever to live, people would die from accidents eventually. So after resurrecting the first few thousand humans, regeneration would allow them to respawn like in a video game. At first, this regeneration did what it was supposed to, ensuring nobody would ever face oblivion again.

Unfortunately, the First War would threaten all of that.

The First War of the New Real
The First War was a raging bloodbath. There were no horrific chemical weapons, no concentration camps, no nuclear weapons, no collapsed skyscrapers, no beheadings of infidels. It was just death after death as people took out their angry vengeance and cravings for power on each other with no restraints, fueled by religious and biological differences with no compassion for whoever each individual hated.

Aftermath
The war resulted in Project Avatara, or "the Changes", where the Descendants isolated each and every person revived so far, who were told they could not keep their ancestry. They had lost the right to be human with their actions, so as a punishment, they would have to be something else. Some chose animals, some chose what they assumed the Gods were, some chose more exotic forms. None were allowed to remain human, and although the effort was benevolent, the Changes are still viewed to this day as a tragedy because generations lost their humanity for acting like human beings.

The result was that no one knew where anyone else was from, and this remained in place for thousands of years, in spite of resurrections happening in chronological order. By the time the Changes were no longer mandatory for new resurrections, the most recent revivals had died in 100 BC/BCE (9900 on the New Human Era Calendar).