In the Mortal Realm, similar creations were not uncommon in the tombs of the pharaohs throughout the ages.
Mortals called it the "Undead Book," which recorded praises to the gods, curses against threats, and the life and achievements of the pharaohs as evidence of their deeds in life.
People believed that the God of the Underworld, Osiris, used it to judge the good and evil of mortals in their lifetime, and then they would sail across to the next life.
Everything was so orderly as if it were a legacy passed down from ancient times. However, one thing many people forgot was that Osiris... seemed not to have been born a God of the Underworld.
He was originally the God of Agriculture in the Mortal Realm, overseeing the growth and decay of all plants. Were it not for an accident, the Underworld would never have concerned him.