Syal Antilles, the firstborn daughter of Wedge Antilles and Iella Wessiri Antilles, came into the world in 17 ABY on Corellia. Despite her father's frequent absences due to his commitments to the New Republic Defense Force, she inherited his passion for piloting. During the Yuuzhan Vong War, Syal, along with her mother and younger sister Myri, had to escape their Coruscant residence after it fell to the invading Yuuzhan Vong. Iella Wessiri Antilles resumed her duties as an Intelligence officer, while Syal and Myri were sent for their own safety to a Jedi sanctuary located in The Maw.
Several years after the Yuuzhan Vong War concluded, Syal and her family relocated to Corellia, the Antilles family's ancestral home. There, she finished her education and later enlisted in the Galactic Alliance Defense Fleet as a starfighter pilot. Her training was overseen by Tycho Celchu, a former wingman of her father. To avoid undue attention because of her famous parentage, she served under the alias Lysa Dunter. During the Second Galactic Civil War, Syal participated in Operation Roundabout as part of the Galactic Alliance. The ensuing conflicts between Corellian forces and the Galactic Alliance Fleet led to her involvement in combat, including two instances where she faced her father, who was fighting for the Corellians. After her true identity came to light, Syal was reassigned to a different squadron and fought in the Battle of Tralus. She continued her service in the Galactic Alliance military throughout the war, and she also developed a romantic relationship with fellow pilot Tiom Rordan, with the two considering marriage as their bond grew stronger.
As the war progressed, Syal's father defected from the Corellians and joined the renegade Jedi Coalition. Syal then suffered the loss of her fiancé and, despite a promotion to captain, her entire squadron was wiped out when the Corellians deployed the Centerpoint Station weapon against the Second Fleet. Following these devastating personal losses, she became an aide to General Celchu, accompanying him on a secret diplomatic mission to the Jedi Order. After Celchu's negotiations concluded, Syal briefly flew with Celchu in Rakehell Squadron as part of the Jedi strategy to destroy Centerpoint Station. Celchu returned to the Galactic Alliance Fleet during the battle, but instructed Syal to remain with the Jedi and her father. Under Wedge's command, she participated in the battle, even shooting down at least one member of Rogue Squadron. After the battle ended and Centerpoint Station was destroyed, she stayed with Wedge on an extended assignment.
Syal Antilles entered the world as the oldest offspring of General Wedge Antilles and New Republic Intelligence Service agent Iella Wessiri Antilles. Although her birthplace was Corellia, her family had relocated to Coruscant by approximately 20 ABY. Sometime during her early years, Syal and her younger sister Myri were present at the Wedding of Luke Skywalker and Mara Jade, as both of their parents were invited. Along with the other children, including the Solo children and Valin Horn, they were primarily supervised by Booster Terrik during the ceremony, who found their high spirits challenging. He eventually managed to calm the children, including Syal, and protect them during a swoop gang attack aimed at disrupting the wedding. The swoop gang failed to achieve its goal, and Skywalker and Jade were successfully married despite several attempts to sabotage their union.
In 27 ABY, Syal, Myri, and their mother were on Coruscant when the planet fell to the extragalactic Yuuzhan Vong invaders. As the defenses of Coruscant collapsed, the three escaped the galactic capital and made their way to the New Republic garrison on Borleias, which was under Wedge Antilles' command. Following a joyous reunion with their father, Syal and Myri were transported to The Maw on the Millennium Falcon, along with several Jedi younglings. Syal, who was ten years old at the time, was hesitant to leave, but Wedge insisted it was for her safety and his peace of mind. Han Solo, the pilot of the Millennium Falcon, cheered her up by having the protocol droid C-3PO give Syal a piggyback ride to the ship, while Solo carried Myri in the same manner. Han and his wife, Leia Organa Solo, then safely delivered the children to the Maw Installation without incident, where they remained.
After the Yuuzhan Vong were defeated by the Galactic Alliance, the governing body that had succeeded the New Republic, Syal returned to her homeworld, Corellia, to pursue her education. She took on a job piloting a freight speeder to help fund her studies; her father promised to match every credit she contributed to her education fund with four of his own, but only if she earned some of the money herself. He also taught her how to fly starfighters, lessons that would stay with her for years to come. Syal would later attend an academy and graduate as a starfighter pilot under the guidance of her father's longtime friend and wingman, General Tycho Celchu.

Following the Swarm War, in which the Galactic Alliance triumphed over the Killik Dark Nest, Syal enlisted in the Galactic Alliance Defense Force as an ensign. In a Ralltiir courtroom, she legally changed her name to "Lysa Dunter" to distance herself from the fame associated with her surname and her father. Under her new identity—and still under the watchful eye of General Tycho Celchu—Syal chose to pilot swift Eta-5 interceptors and was assigned to VibroSword "V-Swords" squadron as VibroSword Seven. As a junior officer, however, she had several nervous habits, including a constantly twitching right leg, which her squadron commander often teased her about. She had not yet experienced combat when VibroSword Squadron was deployed on the Galactic Alliance carrier Dodonna as part of Operation Roundabout, a mission to the Corellian system that marked her first combat assignment. The Corellians had been advocating for greater independence from the Galactic Alliance, and Operation Roundabout was intended as a demonstration of force to the Corellians.
Shortly after VibroSword Squadron launched, a Corellian fleet emerged from hyperspace and positioned itself between the Galactic Alliance ships and Corellia. The two fleets maneuvered for position as they approached each other. At one point, a squadron of Corellian attack fighters began flying directly through the VibroSword Squadron formation. Syal and a Corellian attack fighter flew past each other, but when her squadron leader announced hostile action on the part of the Corellians, Syal maneuvered her fighter so her engines' backblast hit the Attack Fighter less than three meters away from her, which unintentionally destroyed it. The Corellians and Vibrosword Squadron then engaged in a dogfight.
During the skirmish, Syal and the VibroSwords broke through the Corellian unit, but Syal's wingman sustained damage and had to return to Dodonna. Syal then spotted a lone X-wing starfighter and decided to intercept it. To her surprise, despite her own piloting skills, she was unable to lock onto the other craft, which evaded her. When the other pilot broadcast a low-powered signal congratulating her on a maneuver, she recognized her father's voice. Amid the growing tensions between the Corellians and the Galactic Alliance, Wedge had been detained by Galactic Alliance Intelligence as a potential security risk but had escaped; the result of the episode had pushed him into the Corellian camp. For a brief moment, she and the elder Antilles ceased firing, positioning their respective fighters so they could see each other through their cockpits. They exchanged a brief conversation, both expressing concern for each other's well-being. Wedge Antilles subsequently returned to Corellia, and Syal rejoined her squadron, participating once more in the larger battle.
Flying with a temporary wingman, VibroSword Ten, Syal and the rest of her unit were ordered back to Dodonna as the fleet prepared to withdraw to Tralus, one of the other four habitable worlds in the Corellian system. However, seeing an opportunity to engage a Corellian Nebulon-B frigate, Syal stalled for time to attack the larger vessel. Syal ordered VibroSword Ten to target the frigate's shield generators with their missiles, and they complied, despite Ten's objections. The other pilot would have preferred to attack the frigate's hangar bays in hopes of landing a critical hit, but Syal did not want to risk a missile run that might cost her squadmates' lives. However, Syal's choice of target allowed VibroSword Leader to destroy the weakened frigate instead. The squadron then rejoined Dodonna and transited to Tralus, which the commander of the Galactic Alliance Fleet, Admiral Matric Klauskin, had ordered occupied.
As the Galactic Alliance established a base on Tralus, Syal was kept busy flying patrols around the system. Unbeknownst to her, Tycho Celchu had nominated her for selection into a test squadron, while Corellian politician Thrackan Sal-Solo had been attempting to arrange her forced involvement in sabotage missions against the Galactic Alliance. On Dodonna, the chief mechanic approached her and asked to speak with her privately, claiming he had messages from home. The man then attempted to coerce her into discreetly aiding the Corellians, implying that her family would be harmed if she refused to cooperate. Syal refused to be suborned and drew her blaster pistol in an attempt to take him into custody. When the mechanic lunged for her pistol, she shot him and was later brought into a hearing with a Galactic Alliance Intelligence officer and her squadron leader.
When questioned about why she was specifically targeted for subversion, Syal revealed her true name. Her squadron leader was outraged and informed her that she would soon be discharged from the Galactic Alliance military. The Intelligence officer dismissed him and told Syal that she could remain in Galactic Alliance service but would have to transfer to a squadron test-flying Aleph-class fighters or serve as a sensor officer on a larger ship. Syal accepted the squadron transfer but asked the Intelligence officer why she had so much faith in her. The Intelligence officer replied that she had once flown with her father but advised Syal to revert to her original name from Lysa Dunter, as her secret was out.
Flying the larger, heavier Aleph as part of her new squadron, Syal was paired with a Sullustan copilot named Zueb Zan. Syal was pleased that Zan did not have an issue with her identity but was displeased with the lack of agility inherent in the Aleph. Now stationed aboard the Mon Calamari heavy carrier Blue Diver, Syal quickly tried to make the best of her new role as a test pilot, flying missions in both space and atmosphere to assess the handling of the new starfighter.
When Corellian craft were detected heading toward the Galactic Alliance base on Tralus, Syal's squadron was launched to intercept. She and her new unit, Gray Squadron, were ordered into the skies over the city of Rellidir and quickly defeated a Corellian squadron sent to engage them, without suffering any losses. The Corellians were attempting to attack the Galactic Alliance base and deny them a foothold in the system, and Syal participated in the subsequent defense of the base.
She and her unit briefly fired on a pair of YT-5100 Shriek bombers approaching the Galactic Alliance base, which returned fire. Syal managed to get on the tail of the two bombers, which, unbeknownst to her, were piloted by Han Solo and Wedge Antilles. Pursuing Solo's bomber, Syal fired upon his craft, while Solo, aware of her identity through his wife aboard the Galactic Alliance flagship, tried to avoid inflicting lethal damage on her Aleph. As Syal positioned herself for a shot from which Solo couldn't return fire, she noticed the bomber beginning to release its payload. To her surprise, Solo had jettisoned a pair of spotter droids, which collided with her fighter. With her fighter damaged, she managed to regain control and realized that the bombers were going to fly through a nearby building's large underground hangar, which would allow them a clear path to the Galactic Alliance base. Syal then discerned that the Corellians also intended to launch a large salvo of missiles through the hangar in the wake of the two bombers and guide them onto the Galactic Alliance position using the spotter droids. She continued her pursuit and, after advising Galactic Alliance forces of her realization, ordered Zan to destroy the building to prevent its hangar from being used as a transport route by the Corellians. Solo also saw her craft and understood her plan. In response, he fired a concussion missile directly under her low-flying craft, throwing her off course and sending her into a ballistic arc back toward the ground. Syal managed to regain control of her badly damaged fighter, but it was too late to prevent dozens of missiles from streaking through the underground hangar and slamming into the Galactic Alliance base. Somewhat disheartened, she and Zan nursed her craft back to Blue Diver.
Later, Syal visited the resort ship Errant Venture for recreational purposes, gambling in the Maw Casino and accompanied by a pilot, Tiom Rordan, who was about her age. She continued to serve on Blue Diver, which was part of the Galactic Alliance Second Fleet. Syal was promoted to lieutenant and given command of Dancer Squadron, but she was estranged from her parents and family, who were initially allied with the Corellians. Her family later joined the breakaway Jedi Coalition after the Corellian government fired and attempted to assassinate Wedge Antilles, and the Jedi Order broke with the Galactic Alliance over the seizure of power by Jedi Knight-turned-Sith Lord Jacen Solo, now co-Chief of State. During this time, she also deepened her relationship with Rordan, a fighter pilot aboard the frigate Mawrunner, and the two decided to marry after the end of the war, which had escalated to the point where the Galactic Alliance was battling an alliance of planets known as the Confederation.

When the Second Fleet, including Blue Diver, was deployed to assist Jacen Solo's flagship, the Anakin Solo, which had come under attack by Confederation forces under the guise of negotiations between Corellia and Coruscant, Syal was part of Blue Diver's starfighter contingent. Solo used a personal fighter, a Blur reconnaissance craft, to escape a Jedi infiltration team aboard the Anakin Solo, but was pursued by Jedi in StealthX fighters. Solo requested fighter support, and Syal, operating under the call sign Dancer One, was among the pilots launched from Blue Diver to assist him. She helped repel the Jedi attackers, which, unbeknownst to her, included the Jedi Grand Master Luke Skywalker, even landing a direct hit on Skywalker's shields. Skywalker and the other Jedi withdrew in the face of the Galactic Alliance starfighters and the realization that a young girl, the Hapan Chume'da Allana, was in the fighter with Solo. After the Jedi withdrew, Solo personally congratulated Syal on chasing off Skywalker and promoted her to captain.
Shortly afterward, the Corellians fired the Centerpoint Station superweapon and devastated the Second Fleet. The blast also killed the rest of her squadron and took the life of her fiancé, causing Syal great sorrow. The remaining Galactic Alliance forces retreated, and Syal was temporarily stationed aboard the Anakin Solo. Not long after the Galactic Alliance withdrawal, Syal was summoned to the hangar bay of the Anakin Solo by the recently arrived General Tycho Celchu, her mentor and a personal friend. Celchu, after sweeping his shuttle for listening devices, invited her in and inquired about her well-being. When she shared her feelings, he consoled her over the loss of her fiancé and squadron. Celchu then informed her that he was there in an official capacity, serving as an analyst to the other co-Chief of State, Cha Niathal. He asked her about fleet morale, the state of the war, and Solo's leadership from her perspective, and she expressed her dissatisfaction and lack of direction in all three areas. In response, Celchu told her that she would be receiving unorthodox orders and instructed her not to resist them. He also ordered her to contact her father, assuring her that doing so would not be treason since she was acting under the orders of a superior officer.

Syal's assignment as Celchu's aide on a clandestine diplomatic trip to the exiled Jedi Order came shortly after a conversation with Celchu. She had previously discovered that the Jedi were located on Endor through her father. Syal, Celchu, and scientist Toval Seyah journeyed to the isolated moon aboard the shuttle Reveille. There, she experienced a joyous reunion with her father. However, Celchu's mission also carried official weight; Niathal had dispatched him, without Solo's consent, to explore the possibility of the Jedi Order's return to the Galactic Alliance. After discussions with several prominent Jedi Masters, including Luke Skywalker, his proposal was rejected. Skywalker was unwilling to subject the Jedi Order to Jacen Solo's authority. Skywalker did, however, present Celchu with a mission that involved preventing the Confederation from acquiring Centerpoint Station and rescuing Tenel Ka Djo, the daughter of the Hapan Queen Mother, who had been abducted by Solo and held as a political pawn to dissuade Hapes from aligning with the Jedi. Celchu initially voiced opposition to the plan, asserting that, as a Galactic Alliance officer, he could not assist the Jedi, despite his personal sympathies for the Order. As part of the Jedi strategy, Celchu consented to a staged surrender of himself, Syal, and his ship—orchestrated by Wedge Antilles with a fabricated blaster threat. This allowed the Jedi to commandeer Reveille for use in infiltrating Solo's flagship and extracting the Hapan Chume'da, Allana. Celchu suggested that he be assigned to a starfighter and permitted to rejoin Galactic Alliance forces, a request Skywalker granted. However, Celchu also assigned Syal to an extended term as a diplomatic liaison to the Jedi.
Consequently, Syal and Celchu joined an impromptu squadron led by Wedge Antilles, known as Rakehell Squadron, to execute a portion of the Jedi operation. Syal, designated as Rakehell Four, found herself in an X-wing for the first time in a combat scenario, although she had learned to fly one from her father during her youth. To prevent them from alerting Galactic Alliance forces to the Jedi's intentions, their communication systems were linked to those of Wedge Antilles, the squadron leader. As Solo approached Centerpoint Station with a task force to seize the weapon, Rakehell Squadron, feigning pursuit of Reveille and its Jedi boarding team toward the Anakin Solo, advanced.
Celchu instructed Syal to remain with the Rakehell formation, while he piloted his own course toward the Anakin Solo, landing in its hangar bay immediately after Reveille, thereby returning to Galactic Alliance service. Syal then rejoined her father, and together they participated with the rest of the squadron in a simulated chase of another transport, Broadside, which also carried a Jedi boarding team, toward Centerpoint Station. On their way, they were intercepted by Rogue Squadron, and the ensuing battle resulted in Syal shooting down at least one member of the Rogues, an action she was initially hesitant to take. Her starfighter sustained minor damage, but it remained capable of hyperspace jumps. However, Rogue Squadron retreated upon the arrival of Confederation reinforcements, allowing Syal and the Rakehells to escort Broadside, its crew having successfully destroyed Centerpoint Station, away from the battle. They also safeguarded the Jedi-allied light freighter Millennium Falcon, which carried the Jedi team from the Anakin Solo and Allana, out of the combat zone. The two freighters and their escort proceeded to a refueling station in orbit around the desolate planet of Gyndine. From there, they returned to Endor, which the Jedi intended to evacuate in favor of a new sanctuary. The Second Galactic Civil War ultimately concluded with the death of Jacen Solo and the reestablishment of the Galactic Alliance under a new Chief of State.
During her early years, Syal Antilles was frequently scolded by her mother for complaining. She also found her younger sister, Myri, irritating due to her messiness as a toddler. During the wedding of Luke Skywalker and Mara Jade, her minder, Booster Terrik, considered her and the other children to be unruly. From the age of ten, Syal had been taught by her parents to think critically and analyze situations instead of simply expressing her emotions. She was reluctant to leave her parents on Borleias, but accepted it as a necessity. Leia Organa Solo later noted that Syal and her sister Myri were adept at manipulating the administration at the Maw shelter to achieve their goals.

As an adult, Syal was a skilled combat pilot, capable of holding her own against experienced pilots like her father and Han Solo in starfighter engagements. However, she was also easily startled and prone to anxiety. She exhibited nervous habits, such as a constantly bouncing leg, which drew teasing from other pilots. Syal was also known to occasionally disregard orders if she deemed them inappropriate. Her devotion to her family, however, led her to break off a dogfight when she realized she was fighting her father. Otherwise, she was dedicated to completing her missions, persistently attempting to engage Han Solo's bomber at Tralus even after her starfighter had sustained damage on two separate occasions.
Nevertheless, the nature of the war, and particularly the leadership of the Galactic Alliance, disillusioned her. Reports of atrocities committed by both sides during the Second Galactic Civil War led her to believe that there was no honor in service. She also felt that the war was meaningless, as it had forced her to fire upon two of her personal heroes, Wedge Antilles and Luke Skywalker. The loss of her squadron and fiancé only amplified her emotional distress. Although she had been dating Tiom Rordan for less than a year, they had informally decided to marry after the war's conclusion, and his death caused her great sorrow. She was relieved to be assigned to a mission to the Jedi Order with her mentor, Tycho Celchu, and Celchu relieved her of her duties to the Galactic Alliance by placing her on detached diplomatic duty. She was then free to fly alongside her father, for whom she had deep affection—calling him "Daddy" even as an adult—and admiration, even shooting down a member of Rogue Squadron on his orders, although reluctantly and in self-defense.
Syal Antilles was initially introduced into Star Wars canon in Star Wars: Union by author Michael A. Stackpole as a child character. While she has been mentioned in other works, her subsequent direct appearances have been penned by Aaron Allston. Allston developed Syal's character further in the Star Wars: Legacy of the Force series, specifically in the novels Legacy of the Force: Betrayal and Legacy of the Force: Fury, where she serves as a fighter pilot in the Galactic Alliance Navy. In Betrayal, Syal's alias, Lysa Dunter, is misspelled as "Lysa Dunton" on four separate occasions. These misspellings are found exclusively in chapter twenty-four. Syal is also listed twice in the Dramatis Personae of Betrayal, both as herself and as Lysa Dunter.