Necropolis

The Necropolis, a town built upon the charred remains of Bakersfield, is the grim aftermath of Vault 12; it is best described by Killian Darkwater: "The climate ain't good, rain or shine." The true purpose of that vault was to keep the doors open regardless of the conditions, which spelled disaster to anyone attempting to seek relief from the radiated aftermath of the Great War. The residents of the Necropolis were ghouls, individuals ravaged by the effects of radiation after the Great War. The ghoul population was divided into three factions - the surface dwellers, led by Set, who were quite intolerant of outsiders (his ghouls attacked any "normies" at sight), the Glowing Ones who lived in the old Vault 12, and who disliked the other ghouls as much as the normal humans, and finally the ghouls living in the town's sewers, who wanted to live a peaceful life and were much more tolerant of outsiders.

Eventually, the town was taken over by a several of the Master's super mutant. An individual called the Vault Dweller killed the mutant invaders, but unfortunately Ian, one of his friends, was killed. The town was eventually raided by a larger super mutant force, and many of the ghouls were killed. Most ghouls, however, managed to escape, leading to the Great Migration across the wastes to towns such as Gecko, Broken Hills and Reservation.

Appearances in games
Necropolis appeared only in the first Fallout game.

Inconsistencies
In Fallout 1, according to the Vault-Tec Vault Locations holodisk, Vault 12 was located in Bakersfield. However, while Necropolis lies to the Northeast of Los Angeles, the actual city of Bakersfield is not far to the Southwest of the Lost Hills bunker (which is not a Vault, it's a military bunker, as suggested by Captain Maxson's log). The location of Necropolis roughly matches the town of Barstow. It can be assumed that while Necropolis was initially placed where Bakersfield is, the locations were moved at a later date to spread them out better along the map.