Literally translated as Tale of the Imperial Capital. A historical fantasy novel by Hiroshi Aramata, Teito Monogatari is a retelling of the history of Tokyo from an occultist perspective, beginning with the Meiji Era and going up to the end of the 20th cetury. Upon his death, the samurai Taira no Masakado cursed the new city and its inhabitants. Over the course of the next thousand years, numerous characters, both fictional and historical, come into conflict with Yasunori Kato, an immortal villain out to harness Masakado's spirit to destroy the city.The novel won the Nihon Science Fiction Taisho Award in 1987, has sold around some 4 million copies in Japan alone, and is widely considered the first major work to popularize Onmyodo (Yin Yang) magic and Feng Shui in its native country. Of course its immense success has resulted in several visual adaptations. In Japan, the most well known adaptation is the live action special effects film Tokyo: The Last Megalopolis. However because the West isn't so inviting to Japanese live action SPFX films (Godzilla excluded), the most known adaptation over here is the really stylized and repulsive anime version known as Doomed Megalopolis. Both adaptations though are (very) abridged adaptations of only the first 1/3rd of the novel, which has never been translated into English.
Teito Monogatari provides examples of the following tropes:
Adaptational Badass: Shigemaru Kuroda. In the anime, he has some mystical powers and can even fend off shikigami.
All There in the Manual: The films and the anime leave you with more questions than answers if you have not read the book. You'd have better luck sticking a camel through the eye of a needle than you would have understanding the entire Teito Monogatari story purely through its cinematic adaptations.
Demoted to Extra: The classic Meiji era writer Koda Rohan had a much more active role in the novel and live action film. But in Doomed Megalopolis, most of his actions are given to Kamo, a fictional onmyoji. Ogai Mori (another famous Meiji era writer), who was also a major supporting character in the book, is just relegated to a cameo in the cinematic adaptations.
Deus ex Machina: Practically any action on behalf of Masakado's spirit or the Bodhisattva Kannon.
Face Full of Alien Wing-Wong: In the anime, Kato and his kodoku-controlled nurse use this to introduce a fukuchu-mushi (worm spirit) in Yukari. The spirit takes the form of a eyeball and is introduced via mouth-to-mouth.
Feng Shui: Along with Onmyodo magic, it was the first modern fictional work to popularize Feng Shui in the Japanese media. This popular interest would serve as a lead up to the academic feng shui "boom" in 1990's, where many Japanese scholars started studying the practice's influence in the history of their country.
It's believed that Baku Yumemakura's incredibly popular Onmyoji series (also made into a film of the same name) was written in response to the success of this novel (the first Onmyoji short story emerged 3 years after Teito Monogatari started being published).
Within the franchise itself, the disgusting imagery in Doomed Megalopolis was most likely inspired by the commercial success of hyper violent, perverse "adult" anime like Legend of the Overfiend. Also, the excessive perverse horror elements in Teito Monogatari Gaiden were most likely inspired by the commercial success of Doomed Megalopolis.
Full-Frontal Assault: In the climactic battle at the end of the anime, Keiko ends completely naked due to Clothing Damage. In this case, her nudity symbolizes her newfound spiritual purity as a Bodhisattva which is how she defeats Kato.
Genre-Busting: Although Western distributors have insisted upon classifying its adaptations as Horror, the original novel constantly gets classified as Science Fiction by the Japanese. However, it can't be just Science Fiction because it also has heavy elements of magic and folklore in it, placing it closer to Fantasy. In fact, the author first described the novel to an English audience as a "fantasy romance". Also all the historical infodumping in the novel brings it closer to Historical Fiction.
Giant Flyer: In the anime, Kato summons a gigantic, flying manta ray-like spirit to besiege the Tatsumiya house.
The Ghost: Taira no Masakado. Subverted in the anime, in which he appears under the form of a ghostly samurai.
Grew Beyond Their Programming: At the end of the live action version, the robot Gakutensoku momentarily becomes sentient to defend his master (the historical character Dr. Makoto Nishimura, who is played by his real life son Ko Nishimura) from the last of Kato's shikigami. This is never explained, although it somehow fits with the mysticism around Gakutensoku.
Historical Fiction: Imagines the history of Tokyo as influenced by the Supernatural. Also works in numerous historical persons into the plot.
Hypothetical Casting: Realized in the form of actor Ko Nishimura, who got to play his real life father Dr. Makoto Nishimura in the live action film. Also legendary Kabuki actor Tamasaburo Bando V was allowed to portray his favorite author Izumi Kyoka in the live action film as well.
Market-Based Title: In Japan most of the adaptations are simply titled Teito Monogatari like their source material. But in the West, the OVA adaptation is called Doomed Megalopolis and the live-action adaptation is called Tokyo: The Last Megalopolis and both were marketed purely as horror titles. Apparently Tale of the Imperial Capital doesn't sound ominous enough.
Mentor Occupational Hazard: Justified. Hirai sacrifices himself to show his devotion to the Meiji Emperor (who has just passed away). It also happens to divine the year of Tokyo's destruction.
Mr. Exposition: The series is extremely guilty of this. Several of the characters are based on real life intellectuals or scientists and they've got a lot to say. This is partly because the author Hiroshi Aramata's profession was a non-fiction writer, scholar and translator before he wrote this work.
Onmyodo: The first modern fictional novel to popularize onmyodo mysticism in the Japanese media. The whole first portion of the novel is the battle between two rival factions of Onmyoji. Only the Tsuchimikado family, the faction that serves the Emperor of Japan, is considered to be the official Onmyoji.
Sealed Evilina Can: Taira no Masakado could qualify as this, but the twist is that he serves as a Guardian Spirit if his rest isn't disturbed.
Sequel Hook: At the end of the credits to Tokyo: The Last Megalopolis there is a tagline that says "Yasunori Kato will return". Also character dialogue at the end implies that the heroine Keiko Tatsumiya would also return. The resulting sequel Tokyo: The Last War only followed one of these promises and turned out to be a disappointment.
Squishy Wizard: The anime version of Yasumasa Hirai is a subversion. While not a hand-to-hand fighter, he is pretty agile and sturdy, even surviving to an arrow through his torso. But he commits seppuku shortly after.
The Tokyo Fireball: Pretty much the whole series is about the citizens of Tokyo coming to terms with the historical disasters afflicting the city. Remember, it covers 90 years of the 20th century history of Tokyo... A lot of happened to the city during that period.
Trope Maker: Many modern artistic representations of onmyoji in popular culture owe a lot to this series (including the idea of the Black vs. White Onmyoji clans). Also, the demonic sorcerer wearing an Eastern style military outfit. M. Bison of Street Fighter fame is undoubtedly the most popular example of this.
Who You Gonna Call?: Kato's occult mishaps are always first noticed by politicians, scientists, or writers; all of whom are completely unprepared to deal with the supernatural. To compensate, they have to call in the real occult experts which include the official onmyoji (the Tsuchimikado Family) and a feng shui master named Shigemaru Kuroda.
Ur Example: Practically ALL the supernatural/mythological subject matter is taken from the classic Japanese or Chinese folklore, from the medieval tale collections Uji Shui Monogatarishu and Konjaku Monogatarishu to classic Chinese literature such as epics like Romance of the Three Kingdoms. For example, Kato's magical impregnation of Yukari is based on obscure folktales about the exploits of King Wen of Zhou, one of China's ancient Emperors. Also, the character of Yasumasa Hirai is a direct descendant of the great onmyoji Abe no Seimei, and many of Hirai's actions in the story are directly based on those of Abe no Seimei from those old folktales. And the scene where Koda Rohan chops off Kato's hand is inspired directly from the legend of Watanabe no Tsuna, the proud warrior who chopped off the arm of an oni at Modoribashi Bridge. In fact, the story of Teito Monogatari could be seen as a speculative continuation of all these old stories set in modern history.