[1] Due to the fragmented nature of the Brotherhood, existing in multiple Expeditionary Forces (known as "Chapters"), a set structure is hard to follow.

He added that while "this did make them similar to concepts in Gamma World and Warhammer 40K, he professed that he "just loved the idea of high-tech knights in power-armor", calling their creation "total fan service to me".

They are first shown to be an enigmatic, militaristic cult that the protagonist may join in Fallout, who can be critical to defeating the Master, the main antagonist.

In Fallout 3, the East Coast Brotherhood of Steel were portrayed as an altruistic organization dedicated to protecting the wastelanders from raiders and super mutants.

Depending on the player character's actions in New Vegas, the Mojave Brotherhood chapter can maintain the status quo, make peace with the NCR, or be destroyed.

By the time Arthur Maxson succeeded Owen Lyons as Elder of the Eastern chapter during the events of Fallout 4,[3] the Brotherhood had reverted to their original mission of confiscating and reverse engineering lost pre-war technology, reunified with the Outcasts, and re-established contact with their superiors on the West Coast.

[5][6] A main character of the 2024 television adaptation Fallout, Maximus (Aaron Moten), is depicted as a squire in the Brotherhood's West Coast chapter.

[7][8][9][10] A Brotherhood of Steel member clad in Power Armor is featured as part of a range of Fallout-themed Funko Pop figurines which were first released in 2015.

The theory points to the characters' Roman names and the use of a unique red-and-yellow flag, with PC Gamer's Jody MacGregor saying she "wants it to be true".