In 2020s, Australia discovered a large underground reserve of fossil fuels off of the coast of Antarctica. By this time, fossil fuels are in short supply, which led to conflicting interests between northern Australians, who wished to provide oil for China and for their own benefit, and parts of the south, which would form into the South Australia Federation. The two factions then resort to war.
Over one-third of forces on both sides of the conflict are not governmental soldiers, but rather private military contractors such as Belltower Associates. In the civil war, Ben Saxon leads special task force Strike Team Six during Operation Rainbird, but his team is nearly entirely killed due to faulty information provided by his superiors.
By 2027, the Northern Territory has been placed largely under SAF control. The North's government has evacuated abroad and set up a government-in-exile. Meanwhile, any major uprisings are quelled by mercenary units on SAF's payroll, including one notable incident in which the 12th Regiment of Belltower Associates shut down a revolt in the Northern Territory.