Canon of Changes
A book written by the scholar Genruo, who was a contemporary of the mortal form of Shang-Ti. Though historically passed off as a book of mediocre poems, it was actually a book of prophecy inspired by Genruo's study of Lunarian divination.
Kupopolis Legends
The book's true meaning as prophecy was known to the deity Sung Chiang, who over the course of two centuries stole all existing copies of the book from the mortal world. Because of the dimensional portals which opened up the Web of Worlds in the Legends timeline, Sung Chiang believed the Canon's prophecy was coming to pass, and so worked hurriedly to understand and take advantage of it.
Ambiguities in the text prevented Sung Chiang from divining the full extent of the Canon's prophecy; on the advice of Genruo's spirit, Sung Chiang dispatched his minions to the five other worlds of the Legends Web to search for other prophecies similar to the one written in the Canon.