The sprawling epic centers on the dark destiny of Tokyo, a city built upon a spiritual fault line. A thousand years before the story begins, the Heian period warlord Taira no Masakado led a rebellion against the imperial court. After his defeat and beheading, his spirit did not rest. Instead, it became a powerful onryo, a vengeful ghost whose head was enshrined in what would become the heart of the new capital, Edo, later renamed Tokyo. This act transformed Masakado into a guardian deity, a double-edged sword whose fury could level the metropolis if the spiritual balance were ever disturbed.

The narrative opens in the final years of the Meiji period, as Tokyo undergoes a feverish transformation into a modern imperial capital. Industrialists and politicians, led by the visionary Eiichi Shibusawa, gather to discuss grand plans to remodel the city, seeking to solidify its power through concrete, steel, and Western rationalism. Opposing this vision is Yasunori Kato, a mysterious former lieutenant in the Imperial Japanese Army who has become a master of black onmyodo, the esoteric art of yin-yang magic traditionally used for exorcism. Kato is a twisted prodigy, a creature of immense magical power who has willingly transformed himself into an oni, a demon, dedicated to a single purpose: the complete annihilation of Tokyo. He views the modernizing empire as a hubris that must be punished and seeks to awaken Taira no Masakado's spirit to bring about a cataclysm.

The conflict is established through a series of escalating supernatural battles. Kato kidnaps Yukari Tatsumiya, a fragile young woman who is a direct descendant of Taira no Masakado and whose latent spiritual powers make her the key to unleashing his curse. To stop him, a disparate group of defenders unites. This group includes Yasumasa Hirai, a descendant of the legendary onmyoji Abe no Seimei and a master of white magic; Torahiko Terada, a brilliant young physicist who seeks to understand the supernatural through the lens of science; and renowned Meiji-era authors Koda Rohan and Izumi Kyoka, whose literary expertise extends into the realm of the occult. Their struggle to rescue Yukari and contain Kato’s dark shikigami spirits culminates in a desperate confrontation in 1923, but they fail to prevent the Great Kanto Earthquake, a massive real-world disaster that the novel reimagines as a direct result of Kato’s geomantic sabotage, triggered from the Asian continent with the help of Chinese secret societies.

This is only the first major arc. The story spans nine decades of the 20th century, reimagining key historical events through its occult lens. Subsequent arcs see Kato, who is seemingly immortal, continue his war across multiple eras. During the rise of militaristic Japan, he manipulates events leading up to World War II, even attempting to curse world leaders from afar. One notable arc involves the construction of Tokyo’s first subway line, where Kato’s monstrous spirits attack tunnel workers, forcing the defenders to deploy Gakutensoku, a real-life prototype robot, as a countermeasure. The narrative stretches into the post-war period, touching upon the 1960s Anpo protests and culminating in a final confrontation with the spirit of Taira no Masakado in a fictionalized 1998. The sprawling cast includes a host of other historical figures, from the physicist Torahiko Terada and the novelist Yukio Mishima to the Nazi geostrategist Karl Haushofer, all woven into the epic’s alternate history. The original light novel was published in multiple volumes, with later editions restructuring the saga into a twelve-book cycle, forever cementing its legacy as the foundational text that popularized onmyodo and occult themes in modern Japanese popular culture.