The contingency of Brotherhood of Steel
members on the East Coast of the United States were sent there by the ruling council. Their primary mission was to recover any technology they could locate in the ruins of Washington D.C. When they found the shattered remains of the Pentagon, they discovered Liberty Prime which they believed could help bolster their reputation and military prowess. Following the discovery, Owyn Lyons
received a promotion and reached the status of Elder. His new position allowed him to defy the orders of the ruling council and make the protection of the Capital Wasteland inhabitants from super mutants
and other threats their main mission.
This bold move lead to the formation of the Brotherhood Outcasts. Several Brotherhood of Steel members, including Lyons' second in command Henry Casdin
, expressed their disapproval of their Elder's actions. They were extremely upset at the Elder for abandoning their values and primary goals. But Lyons refused to change their priority to fit the instructions of the ruling council, so in response a large number of Brotherhood members donned armor, grabbed a bunch of weapons, and stormed out of the Citadel
as the "Outcasts" - traitors to the Brotherhood of Steel.
Outcast members can be seen wandering around the Capital Wasteland in groups, searching for technology in an attempt to adhere to what the Brotherhood of Steel was meant to do. They are often accompanied by defensive robots that they've programmed to help fend off assailants.
Operation: Anchorage DLC
The only real story role that the Outcasts play is in the Operation: Anchorage downloadable content, which was the first of five for Fallout 3. In the DLC, the Outcasts recruit the Vault 101 Dweller to complete a military simulation that will grant them access to a vault containing weapons and armor. In the simulation, the player experiences the ferocious battle against the Chinese in Alaska. None of the Outcast members have a PIP-Boy, which is required to enter the simulation. Thus, they allow the Dweller to unlock the vault for them.
At the end of the DLC, once the vault is open, the Outcasts allow the player to take anything they want from it. However, the Outcasts rebel against their leader, who gave the player permission to take what they want. After killing the offenders, the DLC is officially complete.