Time can be divided into several big Epochs (纪元) each of which consists from smaller Eras (时代). In the Divine Tree Ridge's Inner World there are 351 Wheels of Time (岁月之轮) and each of them represents one Epoch; in other words there were 351 Epochs, while 365 is the number of Epochs (纪元之数).[note 1]
Several Epochs were mentioned so far:
- Heaven's Will Epoch (天命纪元): The current Epoch, it includes everything from the Desolate Era till the Current Era.
- previous Epoch: It ended during the Legendary Era and it was likely an Epoch during which the Machine Race prospered.
- Archtruth Epoch: the Epoch of Yellow Cloth Girl.
- Epoch of Buddhism: it was an Epoch in which Buddhism was the main cultivation system.
- It was also implied that every Burial Ground and Ancestral Earth is a relict from one of the previous Epochs.
Every Epoch had its own unique cultivation system, but follows the same route: at the start cultivators are weak and the earth is barren (Desolate Era), civilization then slowly develops and rise (Desolate Expansion Era - Ancient Ming Era) until it reaches the most prosperous period (Emperors Era - Current Era). When development reach the apex, the Epoch will end with a great war (most likely against the Old Villainous Heavens).
In the Current Era almost everything about the previous Epochs is long forgotten. Most people believe, that there were only four Eras: Desolate Era, Desolate Expansion Era, Ancient Ming Era and Emperors Era. The Difficult Dao Era and the Current Era are believed to be a part of the still ongoing Emperors Era, since they are too short to be considered an Era of its own, while the Legendary Era is considered to be just a legend; almost no one believes that it actually existed, not to mention the Primordial Era before it.
The novel begins at the start of the Desolate Era, but the main events takes place from the 11th year of the Current Era. Events of the previous eras are revealed through Li Qiye's memories in the course of the story.