Los

Los, apparently short for Los Anything, is a ghoul city, bordering a mountainous region. The city consists of a dock area and a heavily damaged bridge, with the Vault-Tec Corporate Vault being hidden underneath the city.

Background
Before the war, Los was a thriving and sun-soaked city. It housed the Vault-Tec Corporate Vault, which was built by the company to shelter its employees and provide them amenities, while also allowing them to continue their research in Forced Evolutionary Virus and various other fields.

After the Great War, the city was heavily bombed and turned into an ashen canyon of crumbling building and bombed-out bridges, and the amount of dust and radioactive basin plunged the city into an endless night, the sun can not break this artificial fog. Most survivors of this apocalypse were turned into ghouls.

After becoming aware of their condition, their first objective was to establish a "paradise" free of humans and other mutants, where they can live in peace, and the city was named "Los." Despite wanting to stay between them, the ghouls of Los were friendly and showed great hospitality towards human strangers, allowing them to trade, and thus to survive. But a local civil war in the Vault-Tec Corporate Vault caused major damage to it. Its residents were divided, and a group led by security officer Blake went to the surface.

Once on the surface, Blake formed the Church of the Lost, giving themselves a holy mission to protect people against the Vault-Tec Corporate Vault, as they consider it to hold an evil inside, that should never be released, and he took control of the city.

After that, the Church of the Lost incorporated a sizeable portion of the old ghouls of Los to reinforce their newly created frenetic army. Now the city included those not part of the Church of the Lost, the first inhabitants of Los and some who came from the Vault-Tec Corporate Vault, who were friendly towards all. Those of the Church of the Lost controlled the city and killed or captured people for their bloody rituals or to interrogate them. Los then accepted only ghouls.

Those who were friendly lived on the western and eastern part of the city's bridge. Important friendly ghouls here are an old engineer of the Vault-Tec Corporate Vault - Giese, a merchant Hieronymous and for a moment, an old traveler who comes from the Hub - Harold. Another friendly ghoul and a merchant, Salieri, is found nearby, in the docks. Also, the ghouls of Los manage a Gladiator Pit, an arena where anyone could fight for money and the crowd's entertainment.

Everything changes again in Los when an army of super mutants, led by Attis, attacks the city. They quickly make their way to the only remaining entrance to the Vault and take it over, leaving only a few of their soldiers to protect the entrance from raging ghoul fanatics of the Church of the Lost. Sometime later, a group of Brotherhood of Steel paladins arrive, lead by Rhombus, aiming to battle Attis' army. They were stuck between the Church of the Lost and super mutant soldiers, and only Rhombus survived, having been captured by Blake.

Much later, the Initiate, with information from the Vault Dweller, finds the city. The Initiate liberates Rhombus, kills Blake and comes to fight their way through the Vault-Tec Corporate Vault. Inside, the Initiate activated the self-destruction sequence and the explosion wiped out city ruins on the other side of the Bridge of Los. As it's seen in Fallout 2, the Initiate helped Harold to recover his limbs which prevented him from leaving Los, and he managed to leave the city before its destruction and to go to Gecko.

Appearances
Los appears only in Fallout: Brotherhood of Steel.