Logically speaking, as beings that once stood at the peak of mages, illuminating the world for thousands of years like the sun, moon, and stars, the Divine Lords should be very familiar with the Mage's Handbook. Yet, in fact, even the youngest Imaginary Music Master last read the Mage's Handbook thousands of years ago.
The Divine Domain is the dividing line. Below the Divine Domain are the four levels of the Void Realm, where all mortals have the Mage's Handbook. Above the Divine Domain is the Hell and Heaven, where the Void Realm no longer summarizes the life of mages.
For mortal mages, it is natural to have a Mage's Handbook after death, but this common knowledge does not apply to those above demigods—most demigods do not have a Mage's Handbook appear after death!
