Brotherhood of Steel First Expeditionary Corps

The Brotherhood of Steel First Expeditionary Corps is the force currently occupying the New England Commonwealth; they are the remnants of the Australian Brotherhood of Steel, a peacekeeping force which dwelled in Australia before its' collapse. They are generally a non-aggressive force in New England, focusing on restoring things like electricity, water, and accessible food to the region instead of conquest, but retains a strong military presence in the Caribbean, where it actively attempts to maintain control over the crime-ridden regions of Panama and Central America.

History
The First Expeditionary Corps was, in fact, not an organization created by the Brotherhood of Steel during their time in Australia; the group came into existence after the Sydney Royal Fleet left the ports of Brisbane and Gold Coast, leaving their doomed homeland behind.

The Brotherhood of Steel was once a highly-advanced organization: the creators of Power Armor, hyperspace travel, and the renown Venator-class Star Destroyer. First coming into existence around March of 2020, they originally devoted themselves to patrolling the lower regions of the Great Victoria Desert, later being absorbed into the Australian military as a legitimate military branch due to their breakthroughs in Power Armor. They proved themselves in their first military operation, the Kestrel Purge, when they discovered and destroyed factories producing Protogens for the USF underneath Australia. This proved to be a prelude to a much larger attack, as around the time of the Third Furry War, Empoleon (the leader of the USF) led a large-scale invasion of Australia, which proved to be the Brotherhood's first true war. Though Australia's larger military collapsed, the Brotherhood survived, pushing the USF out of Australia and picking up the pieces of the shattered government.

Over the next few years, the Brotherhood re-built Australia, dealing with internal threats from terrorists and extremists before moving beyond Earth in their old fleet of eleven Venator-class destroyers (all of which survived the early wars beyond Earth, and were retired to the Gold Coast Historical Monument before their reactivation during the Aubergine Conflict)

Territories
The Corps has a strong hold on the six New England states of Maine, New Hampshire, Vermont, Massachusetts, Connecticut, and Rhode Island, with additional presence in the island of Bermuda, Washington D.C's ruins, and New York, which it gave away as an independent colony for survivors. It also has several garrisons stationed in Panama, which it more or less controls.