The Frontier Militia represents a territorial defense pact between the systems of the Frontier.
After the era of IMC-funded expeditions and colonization into space ended, public interest waned and IMC support for Frontier development went into decline. Soon afterwards, a number of major conflicts in the Core Systems was top priority for the IMC and effectively abandoned all investments in the Frontier.
For several generations, life on the Frontier continued undisturbed.
When the IMC returned to the Frontier, the colonists had flourished and had access to plentiful resources. Struggling to meet consumer demands in the Core Systems, the IMC declared their ownership of the resources in the Frontier and reestablished their political, economic, and military presence, citing their investments dating back to the colonization era. After years of failed diplomacy, the colonists banded together and formed the Frontier Militia to challenge the IMC and defend their ownership of the Frontier.
The Militia is a loosely governed mishmash of homesteaders, bandits, mercenaries, and pirates all rising up as 'citizen soldiers' when the need arises. Many homesteaders have taken on a "can't beat 'em, join 'em" attitude regarding working alongside different criminal groups. Naturally the people in this melting pot don't always see eye to eye on how to deal with the IMC's exploitation of the Frontier, but they are unified in fighting against it.
The Militia is loosely divided into brigades. Each brigade is responsible for fighting in an assigned section of Frontier territory, which might span as far as several planetary systems. The Marauder Corps, a.k.a. the M-COR, is a small part of a much larger brigade tied to the Freeport System. Although some brigades are little more than vast pirate organizations, the Militia has enough resources to be a real obstacle to the IMC's ambitions on the Frontier.
The Militia also consists of several fleets, though its is unknown how they are connected to brigades. Fleets could be made up of multiple brigades, or perhaps work independently as extra firepower and transportation. The first fleet to be observed was the 1st Fleet, originally lead by General Anderson aboard the flagship "Redeye". The 1st Fleet was responsible for the return of James MacAllan, the destruction of Demeter, and, indirectly, the defection of IMC Vice Admiral Marcus Graves. Prior to the battle on Demeter, a number of civilian vessels also traveled with the Fleet, many of these ships contained the families and other dependents of Militia soldiers.
Another notable fleet is the 9th Fleet, the Fleet which was ambushed at Typhon. It ended up regrouping with the 1st Fleet and partially destroying the planet, foiling the IMC's plot to destroy Harmony in the process.
The Militia often claims that direct action against the IMC is in the best interests of the homesteaders whom they allegedly represent, but not everyone on the Frontier sees it that way. While many who have settled on the Frontier consider them heroes, others see their actions as senseless terrorism, especially those who are employed by the IMC.
The Militia Headquarters is located at Harmony.
- Sarah Briggs - Suffered as a child at the hands of the IMC and served as a field commander of the Marauder Corps.
- James MacAllan (KIA) - Served as a highly decorated Pilot of the Titan Wars alongside squadmate and friend Robert "Barker" Taube before serving as the leader of the 1st Militia Fleet. He eventually sacrifices himself and all ground forces by overloading the reactor at Demeter and effectively isolating the IMC from the Frontier.
- Cheng "Bish" Lorck - Trained by the IMC as an electrical engineer and served as a Combat Intel Specialist of the Militia.
- Robert "Barker" Taube - Served as a Pilot of the Titan Wars alongside squadmate and friend James MacAllen before being recruited by MacAllen into the Militia. Currently the Commander of the Angel City Elites, or A.C.E's.
- Captain Dunnam - Commanding officer of a rifle squadron of the who appears in the campaign mission "The Refueling Raid".
- Pilot Jack Cooper - A former rifleman and skilled Titan Pilot, currently assigned to the Marauder Corps.
- Captain Cole - Commanding officer of the 9th Militia Grenadiers.
- Captain Tai Lastimosa (KIA) - Veteran SRS Pilot and Jack Cooper's mentor, killed on Typhon by Apex Predators.
- Major Anderson (KIA) - A veteran SRS Pilot and commander of Special Operation 217, torn in half due to injuries sustained during time displacement.
- Bear - An elite pilot and squad leader with the 6-4, a freelance unit of pilots.
- Captain Gates - A former IMC officer and Pilot now serving as a section commander of the 6-4.
- Davis - An elite pilot assigned to the 6-4.
- Captain Droz - A Militia officer and an elite pilot currently assigned to the 6-4.
- Marcus Graves - Former Vice Admiral of the IMC Forces in the Frontier, Graves defected to the Militia following the Battle of Demeter and is currently the commander of all the Militia fleets.