Z-City

Z-City (Z市, Z Shi) is a large city located in Japan. It consists of a business district; a residential district and an abandoned, trashed and deserted area. Saitama and Genos are inhabitants of the latter area, which is home to many Mysterious Beings but has cheap rent. Along with several other superheroes, they defend the city from the many monster spawning in it.

Superheroes

 * Saitama
 * Genos
 * License-less Rider

Monsters

 * Underground People
 * Underground King (Deceased)
 * Kombu Infinity
 * Personification Of A Light Pull Cord (Deceased)

Saitama Introduction Arc
The Underground King leads his forces to invade the overworld, but is killed soon after surfacing.

House of Evolution Arc
Z-City is first mentioned by name when there is a mosquito outbreak caused by Mosquito Girl. Genos ends fighting Mosquito Girl, but is ultimately defeated after Mosquito Girl transforms. Mosquito Girl is then killed by Saitama.

Rumored Monster Arc
The Heroes Association begins an investigation of Z-City especially the uninhabited parts and sends Golden Ball and Spring Mustache to investigate. They do not find the rumored monster, but instead find Kombu Infinity. The A-Classes heroes are defeated, but not before they call back up. Saitama then appears after shopping and beats up Kombu Infinity.

Giant Meteor Arc
A Giant Meteor is heading straight towards Z-City and Genos and Bang are assigned to take care of it