what are the unmentionable times the great rebirth and who are the evil ones

The Unmentionable Times refer to the times that occurred before the Great Rebirth. Really they were times that we would recognize with skyscrapers, electricity and quickly evolving science. These times were considered "dark periods" because of perceived inequality. The Evil ones were simply people that caught against the "Great Rebirth" and who continue to fight against the new order of mass equality and control.

The Unmentionable Times is known best as the time frame before The Great Rebirth