Y-City

Y-City (Y市, Y Shi) is a large city on Earth. Child Emperor's Lab is located in this city.

There are 14 heroes living in this city.

Child Emperor's Laboratory
A laboratory owned by Child Emperor is located in Y-City. He builds and experiments with various gadgets here. He is seen sitting on his movable chair.

Restaurant Mammoth
A gourmet restaurant where Fubuki brought Saitama, Genos and King (it is unknown if Bang came too). It seems to have quite a large menu, which includes; Salads with dressing, sirloin, fillet and butter topping.

Heroes
Number of Heroes by Class:
 * S-Class: 1
 * A-Class: 1
 * B-Class: 3
 * C-Class: 10

Known

 * Child Emperor
 * Great Philosopher

Monsters

 * Jumping Spider (Deceased)
 * Pluton (Deceased)
 * Mirror

Monster Raid Arc
During the Monster Raid, Eyesight attacks Y-City. Pig God defeats her by devouring her whole.

Fall of the Hero Association Arc
The Forest Tribe attempts to invade the city, only to be stopped by Genos.

Supreme Hero Arc
Suiko is facing off against Mirror

Numbers
Y-City is attacked by Jumping Spider, but he is quickly put down by Bang, Genos, and Saitama. They then go to 'Mammoth Restaurant' to have dinner.