The Dark Century is an event that occurs roughly once every 10,000 years that results in 100 years of darkness, war and chaos. Upon the end of the Dark Century peace generally returns to the land although previous civilizations and cities are usually completely destroyed. Often even the shape of the terrain, the position of mountains and rivers, is changed due to the violent nature of this turmoil.
The Dark Century is a period where Angels and Demons as well as mortals are locked in constant turmoil and war. During this period, like a brief eclipse, Samael grows in power and chaos rules.
In the history of Gnostaria the last Dark Century was approximately 500 years ago. There is little chance of another Dark Century occurring in the life time of any of the currently living people in the world.
One result of the Dark Century is that there are many ancient ruins that are left all over the world. Some of them are places built by previous civilizations that survived in some form or another (the Forsaken Graveyard is one such example). Others were consumed into mountains or caves, or lost into the bottom of lakes or the ocean. Some of these ruins are well preserved while in some places only a single stone may exist.
During the course of the Dark Century many ancient magics, legendary items, and arcane knowledge are often lost or locked away. Sometimes magic, knowledge or items from previous civilizations disrupted by this conflict are revealed when the landscape changes.
In modern Gnostaria there are legends that have been passed down over the past 500 years of the war among the Angels and 
Demons, when these supernatural beings warred in the sky and descended onto the world. Entire cities were consumed in fire while others were covered in mountains or mysteriously disappeared into the ocean. Since that time the deities of Gnostaria have not been seen and their existence is known of only through religious practices and churches (although occasionally strange things may happen that may be attributed to one Angel / Demon or another).
Most people are not aware that the Dark Century is a recurring event and after several hundred or thousand years people begin to forget that this event occurred. Ancient texts, many times in unfamiliar languages record stories of the previous events but only elite scholars and occasionally lucky adventurers find these fragments of information.
