PreludeOn Baey XII, 2077, during a routine patrol by a COF patrol squad through one of the streets of Milosgrad, a large group of Primondians armed with firearms began firing from the doorways and windows of buildings on both sides of the street. Unable to take cover as they were ambushed in the open, all members of the patrol squad were killed. Prior to them all dying, however, one requested immediate backup. When the COF reinforcements arrived, the Primondians also fired at them. A massive street battle ensued, and finally came to an end when a virisan bellator joined the fray and killed the last of the Primondian assailants. Shortly thereafter, the COF intercom system for Milosgrad was hijacked and self-proclaimed "freedom fighters" declared a "war of resistance".
After what became known as the Milosgrad Massacre, the Concordian Occupational Forces engaged all suspicious civilians with fury and prejudice. Anyone who was even considered or suspected of being a freedom fighter or connected to them were abducted from the streets and brutally tortured, imprisoned, or even worse. Every few days, small firefights and skirmishes would occur in Milosgrad, Port Prime, and other Primondian cities. To aid the occupational forces, DCS Morsus De Superbia docked outside of Port Prime's harbour.A major battle broke out between the Concordian Occupational Forces and the Primondian resistance on Junith XXIII, when a large group of freedom fighters attempted to storm the Milosgrad city hall. The COF personnel present, however, gunned all of them down. The exchange of bullets also killed several civilian passers-by, which attracted the attention of the Atonement of Harmony -- likely pressured by the Isteroxian Union to stop the conflict. The AoH attempted to step into the Concordian-Primondian matter, but Viktoria Dunwall-Smythe threatened to defund the organization and unenlist all Concordians in Peackeeping. Stubboringly, the Atonement of Harmony backed off. The IU then publicly denounced the actions of the Stratocracy of Domi Concordia and officially placed sanctions and an embargo on the baeccan nation. In reply to this, Embattled Governess Viktoria decreed: "there will come a day when you will regret your stance on this particular issue." After the attempt at taking Milosgrad city hall, the Concordian Occupational Forces contracted the second Harbian perdial titan, PT Kingbreaker, for use in governing Port Prime as the majority of attention shifted towards Milosgrad.
In 2078, the resistance intensified as firefights between COF and the Primondian resistance increased. The battles and conflicts between the Concordian Occupational Forces and the Primondian resistance raged on until 2080, when the main leaders behind the resistance were all captured and publicly executed. After the deaths of their leaders, many of the Primondian rebels saw no further point to fight the Concordians, and handed themselves, went into hiding, or left the country. The dissolution of the Primondian resistance caused the Concordian Occupational Forces to become more all-encompassing in Primondia.