So I created a page about the epochs of ED, and messed up pretty badly by deleteing it. Anyway, here is a summary.
Epochs is a amount of time a cultavtion system rules, such as daoism in heavens will epoch. In the divine tree ridge, there are 351 wheels of time each representing a epoch. Each epoch starts barren with weak races, (desolate era) then grows bigger with advanced civilizations (desolate expansion-ancient Ming era) then to the most prosperous.(emperors era) Each Epoch has some variations(difficult dao era-current era) but they are to short to be really counted as true eras, so it is just accepted as part of emperors era. The current known and confirmed epochs are, Buddhism epoch, archtruth epoch, and heavenswill epoch. Heavenswill epoch is names so because the main system is revolves around gathering 12 heavens wills, and fuseing them to gather. Buddhism epoch is where Buddhism was the main cultivation system, and Archtruth epoch is still unknown. At the end of each epoch, there is always a huge battle resulting in mass extinction, like going up against OTH(old villainous heavens). Only peak existences from those epochs can survive by hiding, or the ones who survive forcefully will almost always create a new cultivation system if there own at the start of a epoch going around a law of the new world. Such existences are, Immortal Demon Grotto Master, and Yellow Cloth Girl. The machine world, is believed to be the most technologically advanced epoch in all the 351 epochs. The Old Villanios Heavens is believed to have existed in all 351 epochs, being the reason for almost all of there extinctions as well.