Tierny

Tierny, a human female, existed during the reign of the New Republic. For a certain time, she struggled to survive and eventually became a member of the First Order, as she believed she was destined for something greater. She eventually rose to the rank of agent in the secretive First Order Security Bureau by the time of the cold war between the First Order and the Resistance. During her time in service, Tierny became known for her forceful and manipulative interrogation methods, which sometimes involved making her targets feel secure. In 34 ABY, the supertanker fuel depot Colossus on the Mid Rim planet Castilon was occupied by the First Order. While there, Commander Pyre commanded his garrison's stormtroopers to detain Team Fireball after discovering that the crew's namesake racer had been used by Resistance members who were trespassing in the First Order's Sector Epsilon 51-3 in the Unknown Regions' Dassal system. Although the mechanics Jarek Yeager, Kazuda Xiono, and Neeku Vozo managed to escape, Tamara Ryvora, another mechanic and member of the team, was captured. Tierny was dispatched to the Colossus to interrogate Ryvora and eliminate any Resistance presence, and Pyre prepared for the agent's arrival.

After landing her shuttle, Tierny was greeted by Pyre and Imanuel Doza, the Colossus's Captain, and they proceeded to Doza's office located in Doza Tower. When Ryvora was brought into the office by stormtroopers, Tierny immediately approached her in a friendly and comforting manner, ordering the mechanic's binders to be removed. When Doza began to interfere in the agent's questioning of Ryvora, Tierny escorted the confused mechanic to the Aces' Lounge, where they could have a private conversation. During the conversation, Tierny attempted to portray the First Order's quest for galactic peace in a positive light, using her well-developed cunning to manipulate Ryvora's feelings towards her friends.

Afterward, the agent revealed to Ryvora that Xiono was not who he claimed to be—he was actually a former New Republic Navy pilot and a member of one of the Core Worlds planet Hosnian Prime's wealthiest families who had been recruited into the Resistance. Ryvora, who believed Xiono was from a poor background, was shocked to learn more about his past when the agent gave her a datapad containing his service record. Shortly after the Colossus's alarms went off and the station began to shake, Tierny left the lounge to investigate, leaving Ryvora under the guard of two stormtroopers.

The agent returned to Doza's office, demanding that the captain inform her of what was happening. Doza, who had secretly been working with Team Fireball members Yeager and Xiono to sink the Colossus in order to sabotage the First Order's communications blackout and contact the Resistance by accessing the transmitter outside Doza Tower, lied and claimed that a reactor malfunction must have been occurring. At Pyre's directive, Doza began closing the Colossus's emergency hatches to prevent the station from flooding. The trio watched from Doza's office as the refueling station slowly sank into Castilon's seas, leaving only Doza Tower above water.

Tierny then spoke with Pyre, and they both agreed that the timing of the alleged reactor failure was suspicious, given that Resistance spies were still at large on the Colossus. After a man informed Tierny and Pyre via comlink that the First Order's jamming signal was not operational, Doza suggested water damage as a probable cause. However, Tierny looked out the window and noticed that the transmitter was above the water line, which caused Pyre to leave to deal with the situation. Although Xiono and his astromech droid CB-23 escaped after contacting the Resistance, Yeager was captured by stormtroopers while stalling so the pair could flee.

Seeing Ryvora as a potential asset to the First Order, the agent decided to recruit her to their side by presenting herself as a kind and understanding alternative to her former colleagues. Tierny treated Ryvora to a sumptuous meal in the Aces' Lounge, telling her she deserved more than the Colossus had to offer. The agent further sought to damage Ryvora's opinions of Xiono and Yeager, expounding on their connections to the Resistance with recorded evidence of their actions. When Ryvora responded that Yeager was only trying to protect Xiono by pretending to be a spy, Tierny countered that the recording showed both were Resistance operatives and that she could not trust the former because he had kept secrets from her.

The mechanic was troubled by the agent's claim, at first disbelieving the evidence provided, but eventually coming to see the agent as a guide and interpreting her evidence as compelling. Shortly afterward, Tierny escorted Ryvora through a corridor on the Colossus, and they encountered a captive Yeager as they passed by. Despite Yeager warning the mechanic that the First Order was manipulating her, the agent convinced Ryvora to continue following her to Doza Tower. Tierny stoked the mechanic's resentment toward Xiono by suggesting that he was deceptive. Aware of Ryvora's desire to become a pilot, Tierny offered her a place with the First Order by claiming they could train her to reach her potential.

When Xiono and his colleagues—Team Colossus—flooded the Colossus as part of a plot to expel First Order forces, Tierny and Pyre were present in Doza Tower. Upon a stormtrooper informing them that they had lost five more troopers, Tierny advised Pyre to bring reinforcements and told him that she was taking Ryvora offworld. Not wanting to lose control of the station, Pyre advocated for a "more aggressive solution" if the station could not be raised but also agreed on taking the mechanic off the platform. After the First Order officers left Doza's office, Yeager—who had been secretly listening to their conversation while hiding in the room with Doza—resolved to not let Ryvora leave the Colossus. At Doza Tower's landing platform, Tierny and Pyre accompanied Ryvora aboard a waiting Upsilon-class command shuttle.

While there, Xiono and Yeager tried to convince Ryvora not to leave with the First Order, but she was still bitter towards them for keeping secrets from her and felt he had made her false promises as a cover for his Resistance operations. Exploiting the conflict between Ryvora, Xiono, and Yeager, Tierny claimed that the First Order was giving Ryvora protection and a new purpose. As the Colossus fired up its hyperdrive to flee Castilon, CB-23 squirted oil, causing four stormtroopers at the top of Doza Tower to fall onto the landing platform. Meanwhile, Xiono and Yeager eliminated the other nearby stormtroopers. Tierny and Pyre engaged in a firefight with Xiono while waiting for their transport to arrive, and then they evacuated Ryvora from the platform alongside a stormtrooper. As the Colossus rocketed into space, the First Order dispatched Major Elrik Vonreg's squadron and a Resurgent-class Star Destroyer to destroy the Colossus. However, the station escaped into hyperspace.

After boarding the First Order Resurgent-class Star Destroyer Thunderer, Pyre and Tierny reported to Captain Phasma on the Colossus's whereabouts, assuring her that the refueling station would soon be in the First Order's grasp. Despite Tierny's confidence in their success, Phasma indicated to the pair that if they could not control the station, then they should destroy it, or she would personally see to their execution. After the conversation, Ryvora was brought to meet with Tierny and Pyre, with the latter indicating that they were eager to hear any information she had to share about her former colleagues. The mechanic told the First Order operatives what she knew of Xiono and Yeager's association with the Resistance but eventually insisted she had told them everything she was aware of. After promising her loyalty to the First Order and agreeing to help hunt down the Colossus, Ryvora was made a First Order cadet by Pyre and Tierny. Although they dismissed the cadet—now given the callsign DT-533—to acquire her uniform, Tierny continued to doubt Ryvora's loyalty.

When Ryvora received a message from Xiono on her personal comlink, she turned the device over to Tierny and Pyre to show her loyalty to the First Order after being persuaded to do so by fellow recruited cadet and former Colossus resident Jace Rucklin. The agent was pleased with the cadet's volunteering of information, giving the comlink to Pyre to use. The First Order traced the comlink's signal to the former Resistance planet D'Qar, which had been the site of a recent battle between the First Order and the main Resistance fleet. Tierny deduced that the Colossus's crew were unaware of what had transpired and traveled to the location to rendezvous with the rest of the Resistance. Aboard the Thunderer, she traveled to the world to find the Colossus stranded amongst the debris over D'Qar, unable to make the jump to hyperspace, as the crew had initially planned to refuel at the Resistance base.

With no other options, Xiono led a team to salvage hyperfuel from the ruined Mandator IV-class Siege Dreadnought Fulminatrix. The Thunderer arrived while the Resistance cell was still aboard the wreckage, and Tierny launched an attack on the Colossus; thanks to intelligence provided by an officer, her forces opened fire on what remained of the First Order Star Dreadnought. Doza deployed the Aces to counter the offensive, aiming to protect both his space station and Xiono's team amidst their coaxium extraction effort. Tierny watched the space battle from the Thunderer's bridge, eventually witnessing a heavily damaged Colossus jump to hyperspace once Xiono's team returned to the station with the needed coaxium fuel. The agent asked Ryvora if she would continue to inform them of any future attempts to contact her by her former colleagues, to which the latter agreed. Although Pyre felt that the cadet should be firmly conditioned to ensure her loyalty to the First Order, Tierny disagreed, believing that Ryvora's state at the time would better help them find the Colossus. The agent later stored the cadet's comlink in her office aboard the Thunderer.

Not long afterward, Tierny devised a plot to capture the Colossus in its damaged state. She hired the engineer Nenavakasa Nalor to track the refueling station in her ship and board the station under the guise of helping them with repairs while secretly sabotaging the station. After accepting Tierny's offer of employment, Nalor traced the Colossus's path for a few days, eventually faking a distress signal that prompted Xiono and his colleague Synara San to bring her aboard the refueling station. Nalor sabotaged the station's systems using a k-spline component, broadcasted its location to the First Order, and reported back to Pyre so that he credited her account with payment for the endeavor while fleeing.

Despite his initial doubts, Pyre was impressed that the agent's plan seemingly succeeded as the Thunderer arrived at the Colossus's location. However, Xiono and Vozo worked swiftly to reverse Nalor's damage to the station and successfully evacuated the Colossus from the area after getting its systems back online. When the commander pointed out that Nalor had failed to sabotage the station entirely, Tierny indicated that the First Order should execute the engineer if the First Order ever found her again.

While still hunting for the Colossus, Tierny traveled aboard the Thunderer after tracking the station's signal beacon to a location in space. The supertanker fuel depot fled after First Order forces began attacking, but a lone Resistance pilot—Venisa Doza, who had been attempting to rendezvous with the Colossus—entered the area from hyperspace, flying in her X-wing with her astromech droid, Torch. After Doza was caught in the Thunderer's tractor beam, she was brought to the vessel's hangar and met Tierny, who asked about her identity. When the pilot refused to volunteer information, the agent ordered her to be taken into custody and her ship's logs to be inspected for clues.

A stormtrooper informed Tierny shortly afterward that the ship and Torch both appeared fried. Although stormtroopers tossed Torch into a junk pile, assuming the droid to be non-operable, the droid whirred back to life and rescued Doza from her cell. The Resistance pilot took Ryvora hostage while heading to the Thunderer's Bay 2, attempting to convince her to defect from the First Order by revealing her own identity as a member of the Doza family and a friend of Yeager. Doza stunned the young cadet when she refused, and Tierny entered the hangar behind a contingent of troopers. After Torch used explosives to set a TIE fighter aflame, the agent realized the incident was a diversion providing cover for Doza's escape and ordered the area to be locked down.

The agent then signaled to nearby stormtroopers to target a TIE fighter lifting off from the hangar, under the assumption that the Resistance pilot was inside. However, Torch was at the controls, creating another distraction by allowing the ship to be slowly destroyed while the real pilot boarded her starfighter. As Tierny and the First Order forces observed, Torch ejected from the damaged TIE and rejoined Doza's vessel as it entered hyperspace. Soon after this, Tierny requested a meeting with Ryvora and confirmed that Doza had held the cadet captive during her escape. Ryvora, however, lied to the agent, asserting that the pilot had not revealed her identity. Although Tierny doubted Ryvora's statements, she simply instructed the cadet to cooperate with her security debriefing.

The Colossus, still in flight from the First Order, was in dire need of a trans-binary deflector replacement; failure to obtain one would result in the deaths of everyone on the station due to cosmic radiation. Following Xiono and Vozo's theft of one from the First Order supertanker fuel depot Titan, Pyre informed Tierny via hologram from the Titan that the two residents of the Colossus had stolen the part. When the agent inquired whether Ryvora had been in contact with her former colleagues, the commander stated that she had not. Tierny contemplated this information, eventually concluding that the new cadet would be instrumental in locating the Colossus.

After receiving a Resistance distress signal from the Outer Rim planet Varkana, Xiono, Yeager, San, and CB-23 investigated the world while the Colossus remained in its star system. However, the group soon found themselves trapped aboard the ship of the bounty hunter Ax Tagrin, along with the Duros Norath Kev, the Resistance spy who had sent the distress signal and whom Tagrin had captured. After Tagrin alerted Pyre to the Resistance group's capture on his ship, the commander and Tierny traveled to Varkana aboard the Thunderer and then took a transport to the planet's surface. While Xiono and Kev managed to escape the bounty hunter's grasp, San, Yeager, and CB-23 were recaptured and taken to the main hangar of Vargo Spaceport to meet with Tierny and Pyre upon their arrival.

Tierny addressed Yeager by name in a cold manner, expressing regret that their previous encounters had been too brief to allow them to become acquainted, and she led him and San onto a First Order shuttle with the assistance of two stormtroopers. While still docked in the hangar, the agent interrogated the pair using electric shocks in interrogation chairs, seeking information on the location of the Colossus. When Yeager begged her to stop harming San, she ridiculed him for his compassion for the pirate and confronted him about his treatment of Ryvora by keeping secrets from her. She then focused her attention entirely on Yeager, electrocuting him while repeatedly demanding that he reveal how he contacted Resistance General Leia Organa and where else the Resistance was hiding throughout the galaxy. Despite the mechanic's insistence that he did not know the information she sought, Tierny asserted that he was lying, pointing out that Ryvora had told her about his past as a member of the Rebel Alliance.

While the pair briefly debated whether the First Order was manipulating the young cadet, Tierny was summoned to assist with an issue at console A2 and commented that she would resume her interrogation later. When San observed that the agent would not stop until she had her answers, the pair began to consider ways to escape. Tierny, assisting Pyre and another stormtrooper in accessing the memory banks of CB-23 from a console, watched as First Order Lieutenant Galek reported to Pyre that the Colossus had just departed the Varkana system. As the agent observed, CB-23 was then electrocuted by a tech stormtrooper in an attempt to force her to disclose the station's location. When that trooper successfully accessed the droid's main databanks, Tierny ordered them to extract all possible information from CB-23 and then destroy her.

After Tierny left the consoles, CB-23 knocked the stormtrooper unconscious and connected to the system, causing nearby equipment to short-circuit. The agent noticed the power outage as she walked away and headed back toward the area with her blasters drawn. However, CB-23 dropped from the ceiling and knocked the agent unconscious, leaving Tierny groaning on the floor. After Xiono and Kev freed San and Yeager, CB-23 rejoined the group, which fled Varkana aboard a shuttle and eventually returned to the Colossus, escaping into hyperspace.

Having been on the run from the First Order for months, the Colossus eventually attempted to settle permanently on the Outer Rim planet Aeos Prime. However, the First Order tracked them to the world using a probe droid's report, which included an image of Xiono in the Fireball leaving Aeos Prime. Tierny identified the Resistance spy to Galek and Pyre, having been informed of the development by a First Order bridge lieutenant. When the agent mentioned that the world's population had once collaborated with the Rebel Alliance, Pyre declared that they should have eliminated the Aeosians when they attacked them in the past and ordered a course be set for the Aeos system. Upon arrival, the Thunderer began attacking the Colossus as it attempted to escape into hyperspace. Tierny observed the battle from the Thunderer, listening as Pyre directed their Star Destroyer to target the refueling station's engines to disable their hyperdrive. Tierny expressed surprise when Ace Squadron launched a direct attack on their much larger vessel, deeming the move foolish.

While flying in Yeager's ship, Xiono attempted an attack run on the Thunderer's bridge, launching a missile when in range. However, Ryvora's TIE fighter intercepted the projectile as Tierny and Pyre watched, with the officers ducking to brace for impact in the moments before. The Colossus continued its ascent into Aeos Prime's orbit and jumped to hyperspace as the agent looked on from the bridge. She remarked to Pyre that General Armitage Hux would be displeased, though he replied that the general was not whom he was concerned about. Afterward, Tierny and Galek visited Ryvora and congratulated her on her performance in the skirmish, promoting her to second squadron commander.

Shortly thereafter, aboard the Thunderer, Tierny and Pyre briefed Galek and three First Order cadets on recent reports of Resistance activity near the Outer Rim planet Dantooine, with Pyre ordering their vessel to set course for the world since the TIE squadron patrolling that area had lost contact. As the Thunderer jumped to hyperspace, Tierny continued examining a holographic projection of Dantooine. Later, the agent requested that Ryvora meet her in her office aboard the Star Destroyer and inquired about her well-being. As she played with Ryvora's comlink—which the cadet had previously handed over to her—in her hands, the cadet watched the device while asserting that she was doing well due to her promotion to second squadron commander. Tierny acknowledged her past doubts about her but noted that she was wise to avoid being deceived by her former colleague Xiono.

As the agent placed the comlink in her desk's drawer, Ryvora took note of its location. Tierny elaborated on her life before the First Order to the young woman, explaining that she had recruited the mechanic to join them because of her potential. The agent insisted that Ryvora must continue to exceed her expectations but eventually dismissed the cadet when Galek summoned all squadrons to prepare for launch. Upon arriving at Dantooine, the Thunderer engaged a contingent of Resistance escorts and Ace Squadron pilots protecting three shuttles of Resistance recruits. Although Rucklin destroyed one of the shuttles during the ensuing dogfight, Galek was killed in the skirmish, and the remaining combatants escaped. Tierny later met with Ryvora and consoled her over the mission's failure and Galek's loss. The agent then promoted her to squadron commander for the successful destruction of one of the three shuttles during the endeavor under her command, noting that Galek's failure had created the opportunity for her promotion. Despite Tierny's praise, Ryvora was troubled by the conflict between her moral compass and her duties as a member of the First Order.

Following the Dantooine endeavor, Tierny traveled to the Aeos system aboard the Thunderer. In retaliation for having provided sanctuary to the Colossus, she and Pyre oversaw the suppression of the Aeos system with thirteen other Resurgent-class Star Destroyers, bombarding the planet and killing the Aeosians who had assisted the Resistance. The pair then contacted General Hux via hologram from Tierny's office and reported the completion of the attack. However, Supreme Leader Kylo Ren replaced Hux in the terminal's feed and reprimanded both Tierny and Pyre for failing to locate the Colossus. Although Tierny attempted to appease the Supreme Leader, he rejected her excuses and threatened to replace both officers if they failed to complete their assigned objective; Ren used the Force to force them both to draw their blasters and aim them at each other, releasing them only after several moments. The impatient Supreme Leader warned them that he would not tolerate further failures, granting them only one more chance to find the Colossus.

Tierny and Pyre left the office, determined to redouble their efforts. Shortly after their departure, Ryvora used the reprogrammed MSE-6 series repair droid 5-L to sneak into the agent's office and retrieve her comlink from the room's desk. After speaking with an officer to request a report, Tierny returned to her office as the cadet attempted to hide from her. The agent was distracted by 5-L's presence, allowing Ryvora to slip from the room as her superior asked the droid whether it had completed the system upgrade. 5-L beeped at Tierny and hurried from the room, drawing her attention as she also left the room and closed the door.

Ryvora sent a message in mechanic's code to Xiono and Vozo, requesting their assistance in escaping the First Order by meeting her on Castilon. Subsequently, she changed the hangar bay launch location of her upcoming TIE fighter training session to a different hangar bay on the Thunderer. Tierny met with the cadet and Rucklin as she prepared her ship, questioning her about the change in location for her session. When Ryvora claimed that Operations must have relocated it, Tierny instructed Rucklin to assist her, allowing the pair to leave while observing them intently. The pilots then proceeded to the Tashtor sector—where Castilon was situated—for their training session.

A First Order pilot aboard the Thunderer informed Tierny and Pyre that sensors had detected Ryvora's squadron jumping to Castilon. The agent and commander exchanged a look, with the latter commenting that the new squadron leader must have been feeling homesick. Tierny then departed and went to her office, discovering that Ryvora's comlink was missing from her desk, having been stolen earlier. The agent was disappointed by the betrayal—believing she had provided Ryvora with both training and purpose in life—and deduced the remainder of the lieutenant's plan to defect. Armed with this knowledge, the Thunderer traveled to Castilon to intercept the squadron leader. Eventually, the vessel captured her and those who had come to her aid—Xiono, Yeager, and CB-23—as well as Rucklin, catching their shuttle in a tractor beam. Tierny confronted Ryvora about her treachery, lamenting that she had possessed great potential. Although the agent stated that the punishment for treason was death, the recruit declared that she was no longer afraid of her.

Rucklin then revealed to Tierny and Pyre that the Colossus was located in the Mid Rim's Barabesh system, but he was nonetheless led away from the scene by stormtroopers despite his claims of innocence. Xiono and Yeager, hiding in the hangar bay with the shuttle, fled from the vessel as stormtroopers searched it. One stormtrooper emerged from the captured ship, informing Tierny that it was set to self-destruct. She then ordered nearby troopers to retreat, but she was too slow to escape the blast and was thrown to the floor. Alarms sounded as Tierny rose unsteadily; she drew her blasters and began firing at Xiono and Yeager. She instructed the stormtroopers with her not to let them escape as she pursued the pair.

As the agent continued exchanging blaster fire with the Resistance combatants, Pyre ordered the Thunderer's command to travel to the Barabesh system. The commander eventually joined her, chasing Xiono and Yeager out of the hangar and behind a blast door as both sides fired at each other. After witnessing them disappear behind the door, Tierny contacted an individual working for the Thunderer's security and instructed them to issue a Code Red due to the Resistance agents being loose on the vessel. They agreed to lock down all positions, responding affirmatively. Pyre informed Tierny that the Thunderer was en route to the Barabesh system to confront the Colossus, leaving the station with nowhere to hide. She retorted that they might both face the consequences if he was incorrect, stalking away from him.

On the Thunderer's bridge, a stormtrooper informed Tierny and Pyre that Ryvora had escaped and joined Xiono and Yeager as they fled from First Order forces and were last seen in turbolift G-27. Meanwhile, the fugitives sneaked into the engineering section of the Star Destroyer and transmitted a message to the Colossus, warning their colleagues that the First Order was on its way. Pyre and his stormtroopers captured the group shortly afterward and brought them to face Tierny on the Thunderer's bridge. She commended the trio for their tenacity but stated that the First Order would soon crush their resistance. The agent then questioned Ryvora about her reason for betraying the First Order. The mechanic firmly replied that Yeager had given her a family, which Tierny found distasteful.

Moments later, the Thunderer arrived in the Barabesh system near the Colossus, much to the horror of the captured trio on the bridge, who had hoped the refueling station had fled due to their warning. As Pyre ordered the First Order to attack, Tierny mocked that the group could now watch their "family" perish from the Star Destroyer's bridge. A bridge lieutenant informed the agent and the commander that Colossus pilots were attacking their thrusters, to which the former insisted that their shields could not be breached. At Tierny's directive, Pyre left the bridge to prepare a boarding party.

Working in secret, CB-23 deactivated the Thunderer's deflector shields, and an officer on the bridge relayed the news to Tierny. She demanded that they be brought back online, but the lieutenant insisted that they could not. When a blast from an enemy combatant rocked the bridge, Tierny and her troopers stumbled to regain their balance. Yeager, Xiono, and Ryvora used their momentary distraction to take out the troopers, shoot at the agent, destroy the bridge's controls, and flee the Thunderer. Tierny raised her blaster and moved to pursue them, but they made it safely behind a door before she could.

While still on the bridge, Ren contacted Tierny via hologram, with the latter insisting that she had the Colossus within her grasp but needed reinforcements. The furious Supreme Leader berated the agent for her failure, rejected her excuses, and choked her using the Force. Tierny struggled to breathe, grasping at her collar, until Ren eventually killed her. Ace Squadron then fired at the Thunderer's engines for the final time, causing the machinery to explode and trigger a chain reaction—which killed everyone on board. Shortly thereafter, in 35 ABY, the Colossus helped the Resistance defeat the First Order and Sith Eternal cult's forces at the Battle of Exegol.

Tierny possessed brown eyes, dark skin, and a scar on her jaw. She styled her black hair in an elaborate knotted updo to maintain her curls. Having struggled to survive during the era of the New Republic, Tierny sought to restore peace to the galaxy through absolute order. The intimidating agent was a firm believer in ruling with an iron fist, showing little mercy for those who opposed the First Order's goals and prioritizing the eradication of all forms of opposition with unwavering precision. She considered treason against her organization to be one of the most heinous crimes and was prepared to order the execution of those who failed in their duties. While Tierny maintained a collection of blasters in display cases in her office, she otherwise had no interest in art. Pyre and Tierny maintained a functional relationship despite occasionally questioning each other's methods. Some of Pyre's failures resulted in Tierny wielding more power at her rank than she normally would. The commander was often inclined to heed Tierny's suggestions in the hope of avoiding further displeasure from Kylo Ren.

The agent saw great potential in Ryvora and recognized a reflection of herself in the mechanic, desiring her to rise through the First Order's ranks and utilize her skills. By presenting herself as a stark contrast to Pyre's aggressive stormtroopers, the agent employed her persuasive abilities to create division between Ryvora and her colleagues Yeager and Xiono, claiming that they had withheld information from her because they did not trust her. With Ryvora troubled by this revelation, Tierny successfully manipulated her into joining the First Order and becoming a cadet—while also willingly providing information about her former colleagues—including handing over her comlink to her and Pyre.

The agent remained invested in the cadet's progress within the First Order and took pride in her strong performance in skirmishes, granting her both of her promotions—first to second squadron commander and later to squadron commander after Galek's death. She made an effort to ensure her protégé was thriving, taking the time to meet with her in her office. Meanwhile, the agent expressed sharp disdain for Ryvora's former father figure, Yeager, and how she believed he had treated the mechanic. Tierny expressed a sense of betrayal when Ryvora defected from the First Order, failing to comprehend the mechanic's attachment to her "family" from the Colossus. She relished exacting revenge on enemies of the First Order, taking pleasure in the idea of making Yeager, Ryvora, and Xiono witness the Thunderer destroy the Colossus in the Barabesh system.

As a specially trained weapons expert and intelligence agent, Tierny had access to information on enemies of the First Order, including Xiono and Yeager's backgrounds. The agent was a master of manipulation, preferring to lull her targets into a false sense of security. She took pride in her methods and could quickly transition between an icy demeanor and a caring facade. Although she did not often resort to aggressive tactics, the formidable First Order agent engaged in combat with Resistance agents, including torturing Yeager and San on Varkana during an interrogation. During her First Order service, Tierny demonstrated the ability to wield twin blasters against enemy combatants.

As an operative within the First Order Security Bureau, Tierny's attire was uniquely crafted by herself, as a standard uniform was absent. She chose a gray, ribbed undersuit with long sleeves, enhanced knee protection, and the Aurebesh alphabet inscription "FOSB". She complemented this with a form-fitting black chest plate and black shoulder pauldrons emblazoned with the white First Order insignia. A gray-and-black utility belt held standard First Order code cylinders, along with two black holsters containing two black RK-3 blasters, and a sharply angled black helmet with an open face. Completing her ensemble were gray gloves featuring black panels, tall black boots, and gray pants equipped with knee openings worn over her undersuit.

During her assignment to the Colossus on Castilon, Tierny utilized an Upsilon-class command shuttle and was equipped with a holographic datapad. As she and Pyre pursued the Colossus across the galaxy, they jointly commanded the Thunderer. During her time on Varkana, Tierny employed a pair of electric interrogation chairs to interrogate Yeager and San.

Within Tierny's office aboard the Thunderer, two walls featured transparent, illuminated cases showcasing her array of weaponry. This collection comprised five bladed weapons, four rifles, and a blaster. The office's central desk also incorporated storage compartments.

The character of Tierny was introduced in "Descent," the nineteenth installment of Star Wars Resistance's first season, which was broadcast on March 3, 2019. She had a prior, uncredited appearance in a mid-season trailer released on January 9 of that year.

Tierny's name was first revealed in a StarWars.com article titled "Cosplay Command Center, Part 1: Dressing the Resistance for Star Wars Celebration Chicago," penned by Kristin Baver after an interview with Star Wars Resistance art director Amy Beth Christenson. Christenson provided background on the character and suggested cosplay ideas for Celebration Chicago, noting that fans would be properly introduced to the agent by the time of the event, which began on April 11, 2019. A card depicting a Xi-class light shuttle on Castilon—identified as transporting Tierny—was included in the Hotshots and Aces II Reinforcements Pack for Atomic Mass Games' Star Wars: X-Wing Second Edition combat game, released on November 25, 2022. However, in Star Wars Resistance, Tierny uses alternative vessels for her arrival and departure from Castilon.

Sumalee Montano lent her voice to Tierny. Montano had previously contributed to Star Wars Legends projects, voicing Lashowe, a Force Adept, in the 2004 video game Star Wars: Knights of the Old Republic, and portraying Shae Vizla, a Mandalorian, in the 2011 video game Star Wars: The Old Republic. She also worked on the current canon's 2019 video game Star Wars Jedi: Fallen Order as the Partisans lieutenant Mari Kosan. On August 14, 2019, a StarWars.com article announcing the season's trailer revealed that Sumalee would reprise her role in the second season of Star Wars Resistance. The first episode of the second season, "Into the Unknown," premiered on April 15, 2019, at Celebration Chicago, and later on television on October 6, 2019.

Montano expressed that her work on Star Wars Resistance was meaningful and unique due to the franchise's universal appeal, with each voice actor sharing the same enthusiasm. She found the collaborative nature of the animated show, where the cast often recorded together, to be distinct from her video game experiences. She particularly praised Mary Elizabeth McGlynn as voice director and Christopher Sean, who played Xiono, for fostering a team environment. Sean and Myrna Velasco, the voice of Ace pilot Torra Doza, echoed this sentiment, commending Montano's ability to switch from a friendly demeanor to cold and manipulative while recording as Tierny. Montano appreciated the writers' development of Ryvora's story arc and Tierny's role in it, finding satisfaction in the on-screen relationship between two women of color, which promoted diversity and representation. She was speechless upon first seeing Tierny in animated form, amusing the rest of the cast. Montano enjoyed playing Tierny as a villain who pushed Ryvora toward the First Order, appreciating the inherent conflict between the light and dark sides of the Force.

Montano also believed that her character's conviction of not being evil made her a more compelling villain and personally connected with the agent's backstory, also appreciating the pun in Tierny's name resembling "tyranny." While working on Star Wars Resistance, she and Liam McIntyre, Pyre's actor, cultivated offscreen chemistry to enhance their portrayal as First Order rivals. Montano's favorite Resistance scene was from "The Escape," where Tierny and Pyre aimed their blasters at each other, which she enjoyed recording with McIntyre. Star Wars Resistance's head writer Brandon Auman found Ryvora's internal conflict as she was drawn in by Tierny in "No Escape" emotionally impactful, even years after the show's release.

Jason Pichon, an artist at Lucasfilm Animation, created concept art of Tierny on September 27, 2017. Colas Gauthier, another Lucasfilm Animation artist, created concept art of her blasters the following day. For the season two episode "Rebuilding the Resistance," Gauthier created two concept art pieces for Tierny's office aboard the Thunderer and the weapons displayed in the room's wall cases, both dated September 20, 2018.

The agent's costume design was based on real-world riot police gear, such as those worn by United States' SWAT teams, as well as Navy SEAL garments. Additionally, the training garments of Navy SEALs influenced the knee padding and ribbing of Tierny's military-style sweater. Her helmet's style was based off of ones worn by the Sith Lord Darth Vader and Imperial Security Bureau Agent Alexsandr Kallus. Christenson theorized that Tierny's shoulder armor could have been repainted from parts of a First Order trooper's kit as part of the agent's customization of her uniform choices. The art director also felt that the agent's hairstyle was drawn simply, probably reflecting that she had a number of naturally lush locks. Tierny's office was designed to include a collection of weapons displayed in cases, which Christenson contrasted to the decorative art collection maintained by Grand Admiral Mitth'raw'nuruodo "Thrawn" as shown in the animated television series Star Wars Rebels.

The original outline of "Descent" featured Pyre arresting and questioning Ryvora, without Tierny's involvement. By the first draft, Pyre was replaced by an "Admiral Tierny," who was then redefined as a security agent from the First Order Security Bureau in the next version. This division originated in the Star Wars: Poe Dameron comic-book series as the First Order's equivalent to the Imperial Security Bureau. Initially, the conversation between Ryvora and Tierny in "Rebuilding the Resistance" was intended as a teaser opener. However, the final version instead featured Venisa Doza's arrival at the Colossus to better establish the mission and plot.

In "The Escape: Part 1," Tierny recognizes that Yeager and Xiono booby-trapped their shuttle and alerts her troopers that it is a setup. The StarWars.com article "Bucket's List Extra: 5 Fun Facts from "The Escape - Part 1" - Star Wars Resistance" revealed that her reaction was deliberately phrased to avoid echoing the iconic Star Wars catchphrase "It's a trap!," which was introduced in the 1983 original trilogy film Star Wars: Episode VI Return of the Jedi, spoken by Admiral Gial Ackbar. In audition scripts for Star Wars Resistance, Tierny's name was altered, which her voice actor Montano suspected was to conceal her identity.

During the production of Star Wars Resistance, discussions were held about expanding on Tierny's background. However, Auman stated in an interview that they intentionally kept her origins vague and undefined. He suggested that while she might have fabricated her background to manipulate Ryvora, he personally believed Tierny was truthful. Auman speculated that her family, if any, may have suffered due to the Empire's fall, leading Tierny to attempt working within the New Republic before ultimately joining the First Order—formed from the remains of the Empire—after recalling her family's Imperial ties. The showrunner suggested that many First Order characters likely had tragic pasts and joined after witnessing the New Republic's shortcomings.

Auman indicated that Tierny and Pyre were, to some extent, equals—mainly because Tierny had gained significant power following some of Pyre's failures. The showrunner considered the scene where they were forced to aim their blasters at each other by Kylo Ren to be one of the darkest moments in Star Wars Resistance, noting that Pyre often obeyed Tierny out of fear of the Supreme Leader.