The 4th Hierarchical City of Naobi (第四階層都市「ナオビ」 Dai-Yon Kaisō Toshi “Naobi”) is the birthplace of Tsubaki Yayoi.


In year 2193, Relius Clover had managed to find the sealed Machine God: Nirvana buried in Naobi. The 7th Agency sent a mercenary troop to retrieve it, while the Control Organization sent their soldiers with the same orders. They met after the mercenaries excavated Nirvana, and then Azrael appeared. Azrael, along with reactivated Nirvana, killed almost everyone present, only the captain of the mercenaries managed to survive, after Kokonoe Mercury injected him with demon cells. This event is known as the Event Weapon Dispossession Operation.

Important people born in Naobi