The Hierarchical Cities are a group of 23 different cities created by the Novus Orbis Librarium in the aftermath of the Dark War. The majority of the world's population reside within these cities.
Despite not being created by the NOL, the Magister's City of Ishana is considered the 0th City of Izanagi.
When the Dark War had ended and the Black Beast had been slain, from its body, seithr spewed outwards and covered the planet in its toxic substance. In order to survive, the NOL created the Hierarchical Cities atop different mountains across the world. Each City follows the same basic plan: on the top of the city resides the NOL branch; higher levels house NOL officials and the upper class, and lower levels are inhabited by poorer citizens. These districts are layered on top of each other as individual plates, held together by a main shaft. Each city holds a cauldron deep within, with the only access being through the NOL branch.
Each Hierarchical City is massive in size, with multiple districts, each of relative size. Because each City is atop a mountain, Ars Magus is used to regulate the weather to habitable degrees. This Weather Control Device corresponds to a cauldron and a Regulation Grimoire to function, and without either, it crashes, sending a City back to its naturally mountainous state.  As Cities are so large, a Gear-type Elevator is used to navigate across the multiple levels - the 15th Hierarchical City of Torifune is said to have the best one across the cities, while the 13th Hierarchical City of Kagutsuchi has a more rundown version; in the cases where the elevator does not reach a district, there are long sets of stairs. The numbering of a city does not reflect how big it is, as the 5th Hierarchical City of Ibukido was once the largest of all 24.
List of Hierarchical Cities
All cities are named after various Japanese Gods.
- 0th City of Izanagi - named after Izanagi-no-Mikoto, one of the creator Gods.
- 1st Hierarchical City of Ookoto - named after Ookotooshio-no-Kami - the first of Izanagi and Izanami-no-Mikoto's children.
- 2nd Hierarchical City of Iwatsuchi -named after Iwatsuchibiko-no-Kami - the second of Izanagi and Izanami's children.
- 3rd Hierarchical City of Iwasu - named after Iwasuhime-no-Kami - the third of Izanagi and Izanami's children.
- 4th Hierarchical City of Naobi - named after Kamunaobi-no-Kami - one of three Gods created when Izanagi removed a curse placed upon him.
- 5th Hierarchical City of Ibukido - named after Ibukido Nushi, a God of expelling impurities.
- 6th Hierarchical City of Yabiko - named after Oyabiko-no-Kami, the sixth of Izanagi and Izanami's children.
- 7th Hierarchical City of Kazamotsu - named after Kazamotsuwake-no-oshio-no-Kami, the seventh of Izanagi and Izanami's children.
- 8th Hierarchical City of Wadatsumi - named after Watasumi-no-Kami, a sea God and the eighth child of Izanagi and Izanami.
- 9th Hierarchical City of Akitsu-Kou - named after Hayaakitsuhiko-no-Kami, the ninth of Izanagi and Izanami's children.
- 10th Hierarchical City of Akitsu-Otsu - named after Hayaakitsuhime-no-Kami, the tenth of Izanagi and Izanami's children.
- 11th Hierarchical City of Shinatsu named after Shinatsuhiko-no-Kami, another name for the Wind God Fujin and the eleventh child of Izanagi and Izanami.
- 12th Hierarchical City of Kukunochi - named after Kukunochi-no-Kami, the twelfth child of Izanagi and Izanami.
- 13th Hierarchical City of Kagutsuchi - named after Hi-no-Kagutsuchi-no-kami, the God of fire and seventeenth child of Izanagi and Izanami.
- 14th Hierarchical City of Nozuchi - named after Nozuchi-no-Kami, the fourteenth child of Izanami and Izanagi.
- 15th Hierarchical City of Torifune - named after Ame-no-Torifune-no-Kami, the fifteenth child of Izanagi and Izanami.
- 16th Hierarchical City of Oogetsu - named after Oogetsuhime-no-Kami, the sixteenth child of Izanagi and Izanami.
- 17th Hierarchical City of Yamatsumi - named after Ooyamatsumi-no-Kami, the thirteenth child of Izanagi and Izanami.
- 18th Hierarchical City of Kanayama-Yamabiko - named after Kanayamabiko-no-Kami, a God born from Izanami's feces and vomit.
- 19th Hierarchical City of Kanayama-Yamabime - named after Kanayamabimo-no-Kami, a God born from Izanami's feces and vomit.
- 20th Hierarchical City of Haniyasu-Yasubiko - named after Haniyasubiko-no-Kami, a God born from Izanami's feces.
- 21st Hierarchical City of Haniyasu-Yasubimo - named after Haniyasubimo-no-Kami, a God born from Izanami's feces.
- 22nd Hierarchical City of Mizuha - named after Mitsuhanome-no-Kami, a God born from Izanami's urine.
- 23rd Hierarchical City of Wakumusubi - named after Wakumusubi-no-Kami, a God born from Izanami's urine.
BlazBlue: Central Fiction Library Entry
- Hierarchical City
Due to the large amounts of Seithr spewed forth from the 'Black Beast' covering the surface, humanity had to build cities and live in high altitude, mountainous areas.
The upper level contains the Librarium branch office, while the higher levels are reserved for the wealthy, Librarum personnel, and collaborators. The poor, refugees, and other indigenous races live in the lower layers.
Hierarchical Cities exist around the world in various regions, and each one is assigned a number. There are 23 Hierarchical Cities known thus far. 
- Gear-type Elevator
Movement in Hierarchical Cities is the same regardless of the city, utilizing Gear-type Elevators. Like most everything else, they are based on Ars Magus.
- Weather Control Device
Devices that control the weather, utilizing Seithr to operate. Due to the destruction of the cauldron in Snow Town by Ragna, their device can no longer control the weather properly, causing large amounts of snow to pile up.
- ↑ BlazBlue Alternative: Dark War, Chapter 1, 2 – 1
- ↑ BlazBlue: Remix Heart, Chapter 07
- ↑ BlazBlue: Continuum Shift, Teach Me, Miss Litchi! Episode 1 - Reunion! The three girls from the Academy!
- ↑ BlazBlue: Central Fiction, Library Mode, Location #001
- ↑ BlazBlue: Central Fiction, Library Mode, Item #009
- ↑ BlazBlue: Central Fiction, Library Mode, Item #018