Battle of Ossus (Second Galactic Civil War)

Jacen Solo, who was serving as the Co-Chief of State, dispatched a contingent of Galactic Alliance Guard personnel to the Jedi Academy situated on Ossus. This detachment was under the command of Major Salle Serpa. At the time, the academy was primarily populated by Apprentices, as the majority of Jedi Knights were absent, having traveled to Coruscant for the Funeral of Mara Jade Skywalker. Due to escalating tensions between himself and the Jedi Order, Jacen's motive for sending the GAG troopers was to coerce the Jedi into submission through intimidation.

Jaina Solo, accompanied by Zekk and Jagged Fel, journeyed to Ossus in search of Alema Rar, discovering only scant evidence of her presence on the planet. The limited traces they found led them to land within the Jedi Academy's hangar. While Jaina and Jag entered the academy, Zekk remained in the Ossus forest. Upon entering, they found the academy seemingly deserted. Jaina initially speculated that Kam and Tionne Solusar had suspended classes for the day in remembrance of Mara, but this proved incorrect. Their investigation led them to the flight control area, where they were surprised to find it under the control of GAG troopers, led by Major Salle Serpa. Jaina then deduced that Jacen was effectively holding the academy hostage. Serpa, however, claimed that the GAG troopers had been deployed to ensure continued amicable relations between the Jedi and the Galactic Alliance. He also asserted that Alema Rar was not present on the planet. Serpa then used the young Jedi as leverage to convince Jaina to stay, preventing her from reporting the situation. He also demanded that they surrender their weapons, neutralizing any potential threat they posed within the academy. Zekk maintained his position in the forest near the academy, providing Jaina and Jag with information and receiving updates from them. Furthermore, he remained in position to potentially ambush the GAG troopers should they launch an attack against the Jedi.

Due to their forced stay at the academy, Jaina and Jag were compelled to suspend their search for Alema. Jaina took on the role of a dorm parent, residing with some of the youngest students at the academy. Jag, on the other hand, assisted with the supervision of the teenage students. As long as order was maintained within the academy, the children were left under the care of the adults, while Serpa focused on securing the planet. Initially, the situation seemed stable, and classes resumed. However, one morning, Jaina sensed that a dire event was unfolding at the academy, threatening its students.

Approximately two weeks after Jaina and Jag's arrival at the academy, in the early hours of the morning, Jacen ordered Serpa to deploy coma gas to incapacitate the adult Jedi. The gas induced a deep sleep in Jaina, but she was roused by the voices of Ben Skywalker and the frightened children. Despite being awake, Jaina was unable to open her eyes and had to rely on the Force. Regaining her composure, she used the Force to detect a GAG trooper spraying the coma gas into her dormitory room. She telekinetically hurled the trooper against the wall outside her door, rendering him unconscious. Using the Force again, she opened her door, allowing fresh air to flood into her room. Once she had replenished her oxygen supply, she exited her room, discovering that the dormitory was devoid of all young ones. Looking outside, she observed the younglings and Padawans being herded towards the Central Exercise Pavilion by GAG troopers.

Serpa strategically directed the groups of younglings and apprentices, arranging them in alternating rows of taller and shorter children, separated by GAG troopers. Once the formation was complete, Serpa selected specific Jedi, instructing them to form a circle around him in the pavilion. He organized them based on gender, species, and height. Witnessing this, Tionne Solusar angrily marched to the pavilion, intending to stop Serpa from harming the young ones. Tionne demanded that he return the Jedi to their beds, promising forgiveness for his poor judgment, but Serpa interpreted this as a threat and shot her in the leg.

At this point, Jaina's patience reached its limit. Jag managed to reach her dormitory and informed her that snipers were positioned around the dormitories, awaiting the emergence of the adult Jedi to shoot them. Jaina decided that they needed to eliminate the snipers swiftly and silently. The two exited the dorm, and Jaina located two snipers concealed behind a bush. She successfully distracted them, causing them to look in the opposite direction, allowing her to approach them from behind. She then snapped their necks, killing them. She took one of the rifles, but during this time, another shot was fired at Tionne, causing her to cry out in pain. This triggered Kam Solusar's anger, which continued to escalate.

Jaina ascended to the roof of her building, intending to eliminate the two snipers stationed there, but she was too late. Jaina heard another shot being fired, and Kam Solusar fell for Serpa's trap. He rushed out of his dorm and was shot three times by one of the snipers on the roof. Jaina swiftly killed both snipers, dropped over the roof's edge, and saw Tionne curled up at Serpa's feet, missing the lower parts of one of her legs and one of her arms. This, coupled with Serpa's taunts, accusing Jaina and Jag of cowardice for remaining hidden, prompted Jaina to open fire on the GAG troopers. She signaled the young ones, who then turned against the troopers. The Jedi used the Force to disorient and injure the GAG troopers, and the older Padawans engaged in hand-to-hand combat with them. Jaina knew she had to apprehend Serpa, so she ran towards him. As she ran, she saw young ones on the ground with blaster burns. Jaina reached Serpa and demanded his surrender, which he refused. Serpa was about to shoot Jaina, but Zekk emerged unexpectedly, lightsaber in hand, and severed Serpa's arm. Serpa realized he had no choice but to surrender, and Jaina, Zekk, and Jag captured him and the remaining GAG troopers, most of whom were appalled by Serpa's orders.

Zekk and Jag remained on Ossus to await the arrival of additional Jedi Knights, while Jaina traveled to Kashyyyk. Upon her arrival, she informed Luke of the events that had transpired. Neither Luke, Jaina, nor any of the Jedi could comprehend Jacen's actions. This, along with Jacen's destruction of the Kashyyyk forests and torture of Ben, led Luke to task Jedi Master Kyp Durron with developing a plan to track the fallen Jedi's movements.

The apprentices would later be relocated to a secret base on the Sanctuary Moon of Endor.