Learn this book in exchange for your own blessings, such as being poor all your life, dying alone, or being disabled, and not knowing when you will die unexpectedly. The way of inheritance is that the person who gets the book will have a master from the underworld to teach spells. You can use it at will, or you can hurt others, but there will be retribution. As for the contents of the book, there are things that make people cook badly, things that turn leaves into fish, things that kill pigs, and so on. However, it is useless for ordinary people to study this. Although they exchange blessings for mana, not everyone has the conditions to achieve it. Many people can't find this book, so they can only read it, because their cultural level doesn't understand at all, and Teacher Yin didn't come to teach them. Just learning. Life has not changed.