By reading that book on A History of Magic in Japan, Sherlock came to understand that Japanese magical history had been every bit as chaotic as the struggles for supremacy during the Warring States period.
Several centuries ago, when Japan was still in its Warring States period—roughly analogous to China's Ming dynasty—Japanese wizards had already begun appearing openly before ordinary Japanese people, publicly supporting particular lords or shoguns.
Most Japanese wizards gathered around shrines or temples, often serving in the same shrine, and in its earliest days, Japanese magical history had even been intertwined with Japanese mythological tales.
Even today, most Japanese people still held ghosts and gods in deep awe, even believing in their existence. This stemmed from the ancient phenomenon of wizards and Muggles living together, helping and complementing one another.
Some particularly notorious dark wizards were also given the names of evil yōkai, such as Shuten-doji, Ameonna, Yuki-onna, Hashihime, Hitouban, Enenra, Dōjō-ji Bell, Ibaraki-dōji, and so on...
Even in the surviving illustrations of evil yōkai from Japanese history, these famous monsters were depicted either as wicked people or as human-shaped evil ghosts. The book recorded that in ancient Japan, any evil wizard could be killed by anyone; there was no need to fear breaking any law for killing a bad wizard.
Female dark wizards often caused trouble by using spells that bewitched and confused people.
The most famous among them was an evil witch named Tamamo-no-Mae. She had even used spells similar to the Imperius Curse to bewitch the Emperor of Japan. According to research, the evil witch Tamamo-no-Mae had originated in China's Zhou dynasty and had been driven out by the great Chinese wizard Jiang Ziya.
After arriving in Japan and bewitching its Emperor, she had been driven out by the local great wizard, Abe no