Hierarchical City

A Hierarchical City (階層都市, Kaisō Toshi) is a term used to describe cities that were built after the Dark War which left a large amount of hazardous seithr that covered the world. After the Dark War, a lot of humans and animals became tainted with the seithr and died off, save for the Kaka Clan. Humans were forced to move to high-altitude areas and create cities there.

List of Hierachical Cities

 * The 0th City of Izanagi (第零都市「イザナギ」)
 * The 1st Integration City of Ōkoto (第壱統合都市「オオコト」)
 * The 2nd Hierarchical City of Iwatsuchi (第二階層都市「イワツチ」)
 * The 3rd Hierarchical City of Iwasu (第三階層都市「イワス」)
 * The 4th Hierarchical City of Naobi (第四階層都市「ナオビ」)

The Ikaruga Federation

 * The 5th Hierarchical City of Ibukido (第五階層都市「イブキド」)
 * The 6th Hierarchical City of Yabiko (第六階層都市「ヤビコ」)
 * The 7th Hierarchical City of Kazamotsu (第七階層都市「カザモツ」)
 * The 8th Hierarchical City of Wadatsumi (第八階層都市「ワダツミ」)
 * The 9th Hierarchical City of Akitsu-A (第九階層都市「アキツ―A」)
 * The 10th Hierarchical City of Akitsu-B (第十階層都市「アキツ―B」)

The Izumo Region

 * The 11th Hierarchical City of Shinatsu (第十一階層都市「シナツ」)
 * The 12th Hierarchical City of Kukunochi (第十二階層都市「ククノチ」)
 * The 13th Hierarchical City of Kagutsuchi (第十三階層都市「カグツチ」)
 * The 14th Hierarchical City of Nozuchi (第十四階層都市「ノヅチ」)
 * The 15th Hierarchical City of Torifune (第十五階層都市「トリフネ」)

Outside Izumo Region

 * The 16th Hierarchical City of Ōgetsu (第十六階層都市「オオゲツ」)
 * The 17th Hierarchical City of Yamatsumi (第十七階層都市「ヤマツミ」)
 * The 18th Hierarchical City of Kanayama (第十八階層都市「カナヤマ」)
 * The 19th Hierarchical City of Kanayama (第十九階層都市「カナヤマ」)
 * The 20th Hierarchical City of Haniyasu (第二十階層都市「ハニヤス」)
 * The 21st Hierarchical City of Haniyasu (第二十一階層都市「ハニヤス」)
 * The 22nd Hierarchical City of Mizuha (第二十二階層都市「ミズハ」)
 * The 23rd Hierarchical City of Wakumusubi (第二十三階層都市「ワクムスビ」)