The Brotherhood of Steel is one of the most powerful factions in the Fallout series. Their ambitions to obtain prewar technology, eradicate all non humans, and protect mankind from the horrors of the nuclear fallout makes them capable of great good and great evil.
The Brotherhood of Steel has changed greatly since it’s founding with splinter groups and new chapters appearing over the course of the games. Some of these organizations have obtained great power, while others quickly fell to the wasteland.
The Appalachia branch was the first chapter ever created by the Brotherhood of Steel. Their base was initially set up in Camp Venture before they relocated to Fort Defiance as it was a better staging area. This chapter was dedicated to the recovery and assistance of the other survivors from the nuclear holocaust.
During the events of Fallout 76 they are obsessed with eliminating the Scorched and their leader the Scorchbeast. Despite their best efforts they were unable to defeat the Scorched and they were slowly overwhelmed. They fought to the last man to buy mankind time to find a way to defeat the horrific beast.
8 Texas Chapter
After the events of Fallout some members had a strong hatred of super mutants and saw them as a threat to mankind. High Elder Rhombus broke away from the main chapter to launch a crusade against a growing army of super mutants in Texas led by Attis.
They founded a base in a prototype Secret Vault and became embroiled in a war against Attis’s army and the Church of the Lost. The Brotherhood of Steel lost and their leader was killed. Attis took advantage of the chaos and infiltrated the Vault, killing nearly all of the soldiers entrenched there and ending the Texas chapter.
7 Circle of Steel
The Circle of Steel, not to be confused with the secret police of the Brotherhood, is a group of soldiers who were outfitted with Stealth Boys during the war with NCR. The Stealth Boys caused the soldiers to develop delusions, paranoia, hallucinations, and ultimately schizophrenia.
Seeing the negative health effects the group of soldiers were pulled from duty by their leaders. Assuming the worst, the soldiers stole their Stealth Boys and other gear and fled into the desert, forming the Circle of Steel. Their fate is unknown, though it’s likely their paranoia caused them to turn on each other.
The Outcasts were originally part of another chapter known as the East Coast Brotherhood, but formed their own chapter after a disagreement over ideology and the organization's priorities. The Outcasts settled in Fort Independence and dedicated themselves to reconnecting with the Founders and collecting and preserving prewar technology.
This rebellion didn’t last long as they were ultimately unable to reconnect and new leadership prompted them to rejoin their original chapter. Their rejoining would benefit the East Coast Brotherhood tremendously.
5 Mojave Chapter
This chapter is stationed in a bunker in Hidden Valley in the Mojave Wasteland. The facility has massive underground fans that enable the soldiers to create artificial sandstorms, this is done to discourage curious locals, hide their movements, and avoid detection by anyone trying to find them with technology.
Though small, they have been an effective chapter by utilizing guerrilla tactics to fight the NCR and other factions. In fact, the ruler of New Vegas, Robert House, considers this band of soldiers to be one of the greatest threats to his empire.
After all these years the founders of the Brotherhood of Steel or the main chapter remains a powerful and capable force. Headquartered out of the Lost Hills bunker in California they have many bunkers and outposts throughout the state and were able to maintain an aura of secrecy until confronted by the NCR.
Unfortunately, they expanded too far too fast and they became largely decentralized with each bunker forming their own rules and conducting their own missions. This led to the destruction of many outposts during the war and the leaders are struggling to regain control in its aftermath.
3 East Coast: Commonwealth
The Commonwealth branch is the first chapter established by the larger East Coast Brotherhood of Steel chapter. This chapter has tremendous air superiority thanks to the Prydwen airship in their possession that allows them to conduct quick strikes anywhere in the Commonwealth.
Their troops are also some of the best outfitted in the Brotherhood of Steel and come with standardized energy weapons and the elite soldiers are outfitted with T-60 power armor. Stationed at the Boston Airport base they are strong and capable fighters who have a hatred for ghouls, synths, and super mutants. Their goal to secure tech and eliminate these races has made many locals their allies and enemies in the Commonwealth.
2 Midwestern Brotherhood
This chapter was the result of its leaders crash landing in Chicago during a recon mission. Isolated from the main group and without air support they were forced to hole up on the outskirts of town and form the Midwestern Brotherhood.
They have proven to be brutally efficient and warlike, conquering large portions of the area. They have successfully fought off the Reavers tech cult, a super mutant army led by their corrupted leader Paladin Latham, and the powerful Calculator and his robotic army. Surprisingly these warriors willingly welcome anyone and everyone into their ranks such as ghouls, sapient deathclaws, a handful of defected super mutants, and even some reprogrammed robots from Vault 0. They are incredibly ruthless and immensely powerful.
1 East Coast Brotherhood
By far the most powerful chapter of the Brotherhood of Steel has to be the East Coast Brotherhood. Sent to settle into the east coast they have built the mighty Citadel in the ruins of the Pentagon and rule the area with a power armored fist.
Their top priority is the destruction of super mutants and see preserving and obtaining prewar technology as a side project to further their primary goal. This led to them being cut off from the main chapter and a few rebels to break away and form the Outcast. Nevertheless, they have dramatically grown their numbers through massive recruitment efforts, with new leadership were able to consolidate the Outcasts back into their ranks and repelled a massive invasion by the Enclave.
They became so powerful they established the East Coast: Commonwealth chapter to continue expansion efforts and have built a fleet of airships to maintain their superiority. They are far more powerful than the western chapters, are largely considered the future of the Brotherhood of Steel, and a major force for mankind’s preservation.