The Circle

The Circle of Steel is a sub-faction within the Brotherhood of Steel meant for dealing with internal conflicts.

Background
Following the disaster that was Operation: Sunburst, Brotherhood of Steel leaders and Circle operatives marked Elijah for execution. Christine Royce was sent after the rogue elder, equipped with a silenced sniper rifle and CoS recon armor.

Appearances
The Circle of Steel makes a small appearance in the form of Christine Royce in the Fallout: New Vegas add-on Dead Money, it is also mentioned in Old World Blues.

Behind the scenes
According to Chris Avellone, the group was formed by hardliners in the Brotherhood of Steel, who believed the rest of the organization has drifted from the original principles of preserving tech. The Circle of Steel, in terms of their position relative to the Brotherhood proper, are the Internal Affairs of the whole Brotherhood of Steel.