Onmyōji were practitioners of divination, sorcery, exorcism and other mystic arts who reached the height of their power and influence in the imperial court of the Heian Period (794-1185). As concisely explained in the opening of Shimako Sato’s mind-expanding and eye-popping “The Yin Yang Master Zero,” they had their own school for apprentices, who were taught by specialists in various subject areas, including spells and curses, and presided over by a mysterious grandmaster (Kaoru Kobayashi). Think of a Japanese Hogwarts with adults as students.