Serving as the intelligence arm of the First Order, the Security Bureau was staffed by Agents such as Terex, Tierny, and Lieutenant Weel. These individuals were responsible for safeguarding First Order secrets, pursuing Resistance members, and retrieving stolen information. Terex managed a spy network, compelling individuals like Oddy Muva, a Resistance technician, to work for him. Muva's compliance was ensured by Terex's control over his wife, Sowa Chuan, who was held as a slave along with other coerced relatives on his ship, the Carrion Spike. Under the orders of Supreme Leader Snoke, First Order agents and military personnel were forbidden from initiating open conflict with forces aligned with the New Republic, including the Resistance.

During the Cold War's early period, the First Order Security Bureau dispatched agents to gather intelligence on Resistance groups, including Commander Poe Dameron's Black Squadron. After Terex, a former stormtrooper turned crime lord, intercepted a shipment of [stormtrooper armor](/article/first_order_stormtrooper_armor] intended for the First Order, he decided to join their ranks. He then became an agent within the First Order Security Bureau. Following Operation: Sabre Strike, Captain [Phasma](/article/phasma] tasked Terex with recovering information stolen by Dameron from Erudo Ro-Kiintor, a New Republic Senator secretly working for the First Order.

Terex received significant resources, including a Maxima-A-class heavy cruiser, stormtroopers, TIE/fo space superiority fighters, and a First Order landing platform. During the mission to Ovanis, Terex attempted to force the Crèche cult to surrender Dameron through intimidation. Terex and his forces subsequently engaged in a battle with Dameron's Black Squadron, the Crèche, and two winged creatures. Dameron and BB-8 defeated Terex, compelling him to order his forces to cease hostilities. To prevent further conflict between the New Republic and the First Order, Black Squadron allowed Terex and his forces to leave peacefully.

Terex discovered, through his unwilling informant Muva, that Dameron and Black Squadron were traveling to the Megalox [prison](/article/prison] on the high gravity world of Megalox Beta to interrogate Grakkus the Hutt about the whereabouts of Lor San Tekka, an explorer whom General [Leia Organa](/article/leia_skywalker_organa_solo] believed could assist in locating her missing brother, [Luke Skywalker](/article/luke_skywalker]. Terex bribed Warden Luta and the prison guards to abandon Black Squadron within the facility. However, Black Squadron fought their way into Grakkus' fortress. Due to the competing interests, Grakkus decided to provide his information to whoever could free him from Megalox prison first.

Enraged by Grakkus's betrayal, Terex met with rival crime lords Toren, Kan Be, and Isin, identifying himself as a First Order intelligence agent. He hired the imprisoned crime lords to use their gangs to attack Grakkus' palace and kill Black Squadron and Grakkus' guards. Terex intended to kill Grakkus after obtaining the information. In exchange, he offered the crime lords transportation off Megalox. The crime lords accepted and launched an assault on Grakkus' compound. However, Dameron outmaneuvered Terex by having his squadron's astromech droids sabotage the prison's gravity shield, exposing Terex and the gangsters to Megalox Beta's intense gravity.

Dameron forced Luta to allow Black Squadron to leave with Grakkus in exchange for restoring the prison's gravity shield. Terex was rescued by the crew of his starship Carrion Spike. Frustrated by his failure, Terex used the Carrion Spike to attack the orbiting Megalox space station and the rescue shuttles. However, Black Squadron, who inflicted damage on the Carrion Spike, forced him to retreat into hyperspace. Instead of reporting back to First Order Space to face a debriefing for his failure, Terex decided to seek revenge against Dameron.

Subsequently, Lieutenant Weel captured Dameron and Suralinda Javos, a Galaxy Beacon journalist, during a skirmish on Pheryon. He interrogated Javos at a warehouse. Javos, a Squamatan, escaped by using a corrosive spray from her mouth, a distinctive trait of her species. She and Dameron then returned to the Resistance with information about the First Order's illegal rearmament program, which violated the Galactic Concordance.

Driven by his personal vendetta against Dameron, Terex returned to the Ranc Gang's base on Kaddak. After regaining control of the Ranc Gang, Terex initiated an unsanctioned mission to eliminate the Resistance, hoping to improve his standing within the First Order. Terex's strategy involved feeding the Resistance spy droid N1-ZX with false information to track Dameron to the Resistance base. Despite Phasma's concerns that his plan violated Snoke's directive to avoid conflict with the Resistance, Terex was confident that the Ranc Gang would succeed. However, Dameron detected his plan and led Terex and the Ranc Gang to a remote desert planet.

Terex's Ranc Gang forces clashed with Dameron, Black Squadron, and Muva in a skirmish. Muva managed to liberate his wife and the other slaves from Terex's control. Following a battle in space and on land, Terex and his forces were defeated by Black Squadron and First Order forces led by Commander Malarus. After destroying the Carrion Spike and the Ranc Gang's "Uglies," Malarus arrested Terex with Dameron's approval. Aboard a First Order Star Destroyer, Terex requested to speak with Phasma, claiming to possess vital information that could lead to the Resistance's destruction. Terex revealed that the Resistance used an ancient protocol droid to manage their spy network and that he had recovered its memory core. However, Phasma dismissed it as worthless due to an electrical surge caused by BB-8. Despite this, Terex claimed he was the First Order's most valuable agents and still had many secrets to share with the First Order. Phasma agreed to let Terex out of his cell, but decided to give him a brain/cyborg construct in order to control him.

During the First Order's occupation of the Colossus on Castilon, Agent Tierny was dispatched to assist Commander [Pyre](/article/pyre] and his garrison in capturing known Resistance agents. Upon her arrival, Tierny interrogated [Tamara Ryvora](/article/tamara_ryvora], a mechanic, about her employer Jarek Yeager, fellow mechanic [Kazuda Xiono](/article/kazuda_xiono], and their involvement with the Resistance. Ryvora denied any involvement with the Resistance, stating that she only knew that Yeager was friends with Commander Poe Dameron. Tierny believed her and revealed Xiono's background: his wealthy upbringing on Hosnian Prime, his service in the New Republic Defense Fleet, and his subsequent recruitment into the Resistance as a spy.

During the First Order's attack on the Resistance fleet, Colonel [Ansiv Garmuth](/article/ansiv_garmuth] was stationed aboard the Supremacy. BB-9E informed Garmuth that FN-2187 and Resistance fighter Rose Tico had infiltrated the ship. He gathered stormtroopers and informed Phasma of this.

During the Mission to Garel, there is a director named Orlok of the First Order Security Bureau, nicknamed the "Gamemaster" came to Garel to find the Resistance.

The First Order Security Bureau made its debut appearance in the 2016 comic book Poe Dameron 2 and was identified in the following issue, both issues were written by Charles Soule and illustrated by Phil Noto.