How Are Heavenly Masters Trained?

Heavenly Master is an unattainable profession, because you never expect what monsters will appear around you. Life is too short, and we will grow old if we don't catch ghosts. The spells in it are all made up by myself, they have no use, and some movies and TV shows will also be added to it. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.