The Justicars' Brigade, also referred to as the Justicars, functioned as a militia within Coruscant's Underworld during the era of the Cold War. Following the devastating Sacking of Coruscant, the Galactic Republic withdrew the Coruscant Security Forces due to resource constraints, which left the area open to exploitation by dangerous gangs. Enraged by the violence inflicted by these gangs, former Republic soldiers established a militia, naming themselves the Justicars, and embarked on a mission to restore order through brutal means.
After the Sacking of Coruscant, criminal organizations, including Black Sun, exploited the chaos on Coruscant and began to seize control of the planet's lower levels. The Galactic Republic, facing limited resources, couldn't effectively combat this takeover, leading to the withdrawal of the Coruscant Security Force (CSF) to safeguard more critical zones. In response, a collective of former soldiers founded the Justicars' Brigade, a militia that was subsequently shortened to simply the Justicars. Their objective was to defend their homes and reclaim their neighborhoods. As Black Sun's backlash intensified, the Justicars implemented stricter measures to regain control, including imposing curfews and eventually declaring martial law. The territory they seized soon became known as the Justicars' Sector, and an old CSF installation was repurposed as their headquarters and renamed the Justicars' Tower. Armed security patrols were authorized to employ lethal force against individuals lacking the proper clearances as defined by the Justicars.
The Justicar forces continued their campaign to reclaim various sectors of Coruscant, simultaneously acting as a self-appointed security force. However, the Justicars became unpopular with some citizens within their territory. While some viewed them as legitimate law enforcement and military personnel, many perceived little difference between their methods and those of the gangs. Larin Moxla, a former Republic trooper and resident of the lower levels, disapproved of their methods, considering them bloodthirsty and lawless. Initially pleased with the militia's formation and eager to collaborate, the CSF soon found itself forced out of the territory alongside the gangs. The Coruscant government declared the Justicars a threat, leading the Justicars to sever all communication with the outside world. The entrance to their territory was heavily guarded, with access restricted to those possessing the appropriate clearances. Justicar security officers frequently conducted checks and arrested individuals at the taxi speeder station just outside the gate, with minimal interference from the few CSF officers assigned to the area.
Membership in the Justicars was not always voluntary. Civilians caught violating laws, such as curfew within their territory, were sometimes conscripted into indentured service within the Justicar fighting forces. The Justicars either lacked the resources or simply disregarded the need to verify whether a citizen was legally an adult before forcing them into service, focusing solely on their apparent physical maturity.
Towards the end of the Cold War, the Justicars initiated dealings with the Sith Empire for arms and equipment. Several prominent members, including Lars Baddeg and former Havoc Squad commander Jek Kardan, provided direct support to Imperial operations on Coruscant.
The Justicars were conceived for Star Wars: The Old Republic, a massively multiplayer online roleplaying game created by BioWare and launched on December 20, 2011. Their initial appearance occurred in The Old Republic: Fatal Alliance, a novel penned by Sean Williams, released on July 20, 2010.