Guardian Brotherhood

 The Guardian Brotherhood is a group that is described as being on "barely tolerant terms" with the Brotherhood of Steel in The Armageddon Rag, Vol. 3.

Background
Despite the Guardian Brotherhood being on barley tolerant terms with the Brotherhood of Steel they were not above cooperating when it came to a common goal. Elder Francis of the Brotherhood of Steel was eager to build bridges with the Guardian Brotherhood, and was on stable enough grounds to assign training missions with them.

The Guardians took part in a mission to find out if there truly is a tunnel entrance to the Glow which entailed a beach assault working with a Brotherhood of Steel squad dubbed the "Brothers Grimm" by the Guardians because of the tall tales they would spin.

The Guardians squad practices differed from the Brotherhoods in that they used minimal communication on the field, barley any words, or even hand gestures, which Miller, a Brotherhood scribe, found impressive and felt was something to report back to Elder Francis.

Appearances
The Guardian Brotherhood appears in the short story "On the Beach," published in The Armageddon Rag, Vol. 3. They would have likely appeared in Interplay's canceled Project V13, also known as Fallout Online.

Behind the scenes
The Guardian Brotherhood is a reference to Wasteland, the inspiration for the Fallout series. In Wasteland, there is a faction named the Guardians, who are just like the Brotherhood of Steel, and were the inspiration for the Brotherhood of Steel.