Born around 12 ABY, Lon Shevu resided in an apartment in the Port Quarter of the planet Coruscant with his longtime girlfriend, Shula Pakasj. He joined the Coruscant Security Force (CSF) as a police officer, starting with patrol duties. During this time, his girlfriend gifted him a golden necklace, which he wore throughout his career. Shevu became well-versed in the investigative methods of CSF detectives and steadily advanced, achieving the rank of captain before the age of twenty-eight, a young age for such a position, although he appeared older. As a commanding officer, Shevu earned the trust of his subordinates and maintained a hands-on leadership style. He was known for his traditional, by-the-book approach, prioritizing legal procedures over personal feelings. Shevu was appointed head of the CSF's Anti-Terrorism Unit, based at the Galactic City Strategic Center.

In 40 ABY, escalating tensions between the Galactic Federation of Free Alliances and Corellia erupted into a blockade of Corellia. In retaliation, terrorists detonated a bomb at The Elite hotel. The explosion caused transparisteel to shatter violently, disrupting skylanes and causing speeders to plummet. The shock waves created immediate chaos, damaging the surrounding area and causing traffic congestion. Shevu and his Anti-Terrorism officers were the first to respond. Shevu arrived at the Strategic Center to assume command as incident commander, coordinating efforts between the CSF, Coruscant Fire and Rescue, Galactic City Air Traffic Control, medcenter managers, and the Galactic City Authority. The CSF's special Tactical and Operational team began searching through the wreckage, reporting an initial casualty count of one hundred and five dead, with over three hundred injured.

Chief of State Cal Omas of the Galactic Alliance was also present at the Strategic Center, soon joined by Jedi Grand Master Luke Skywalker, Jedi Master Mara Jade Skywalker, and Jedi Knight Jacen Solo. They discussed the political ramifications of the explosion with Shevu. As a law enforcement officer, Shevu refused to confirm that the explosion was a terrorist attack by Corellians until the investigation concluded. However, he informed the group that the Coruscanti Immigration Service reported nearly twenty million Corellians residing on Coruscant. Despite differing opinions on the threat posed by Corellian residents, it was clear that the explosion, which resulted in six hundred and thirty-four deaths and hundreds of injuries, could trigger a full-scale war and further incidents on Coruscant. Shevu remained at the Strategic Center for hours beyond his shift, coordinating response and investigation operations.

Meanwhile, tensions on Coruscant continued to rise. The next day, the Corellian Sanctuary was vandalized by Coruscanti angered by the bombing. In retaliation, Corellian militants contaminated Coruscant's water supply with Fex-M3, affecting areas including the Corellian Quarter. Enraged Coruscanti gathered in front of the Corellian Embassy, and a riot erupted between them and a dozen Corellians standing guard. The CSF responded with dispersal gas and riot batons to regain control. The Galactic City Authority issued a full terror alert, and the CSF doubled its street presence. Additionally, Chief of State Cal Omas and G'vli G'Sil, chair of the Security and Intelligence Council, met with Jacen Solo. Omas initially offered Solo command of the CSF Anti-Terrorist Unit, but Solo declined, suggesting the formation of a new security force separate from the CSF. Impressed by Shevu's dedication and honesty, Solo requested that Shevu and a team of CSF officers from the Anti-Terrorist Unit, as well as a special forces squad, be transferred to his command. Omas and G'sil agreed, promoting Solo to colonel, and Shevu was seconded to the new Galactic Alliance Guard (GAG).

The GAG was quickly established with Shevu, several members of the CSF's Anti-Terrorist Unit, and GAG troopers from the 967 Commando Unit. The Security Council authorized the GAG to intern Corellians who posed a threat to Coruscant. Solo decided that the first operation would be in Jabi Town in the Corellian district of Galactic City. He organized the raid with Shevu and brought his Jedi apprentice, Ben Skywalker. The CSF blocked several skylane intersections with CSF Traffic Division repulsorlift ships before the operation began. Solo ordered that no shots be fired unless fired upon. Shevu suggested amending the order to include perceived threats. Solo agreed, issuing the change and earning goodwill from the troops. After the signal, the GAG entered several residences, led by Solo, and began the internment process. Several people were arrested, and explosives were seized. Towards the end, Shevu reported that they still had to process over fifteen hundred people, but the resistance had been dealt with.

After the raid, Shevu, having grown fond of Ben, sat with him and several sergeants at a table in the Galactic Alliance Guard Headquarters to discuss the raid and watch the news, marking the beginning of a strong friendship. The GAG continued its raids and anti-terror operations. In the Adur quarter, they seized explosives and blasters and arrested thirteen people. Late one night, Solo, Ben, and Shevu raided a building in Coruscant's lower levels to arrest Cotin, Abadaner, Bolf, and Ailyn Habuur, a bounty hunter known as Ailyn Vel. Shevu and Ben led the operation while Solo covered the rear with two squads. Shevu used a loudspeaker to demand surrender, but the suspects fired at the GAG troopers, who returned fire. Annoyed that the CSF hadn't cleared the building, Shevu ordered the use of blasters only. He authorized the squads to enter from the top and had Sergeant Wirut send a flash-bang grenade through the window. The squads stormed the apartment, killing two suspects but not finding the others. Shevu kept Ben close as they searched the building, locating and arresting the remaining two. Solo later left Coruscant for the Alliance fleet over Corellia, leaving Ben in Shevu's care.

Later, Shevu debated with Captain Heol Girdun, a former officer of the New Republic Intelligence Service, on how to interrogate Ailyn Habuur. Girdun wanted to use intelligence service methods, but Shevu insisted on adhering to Senate-established rules for police. Girdun left, and Shevu and Ben questioned Habuur. Shevu remained calm but firm, seeking to understand Habuur's presence on Coruscant and her connection to Mirta Gev. Shevu noticed Habuur's subtle reactions, and Habuur admitted to hiring Gev to find her mother's necklace. Shevu decided to intercept Mirta Gev upon her arrival and asked Ben to have Girdun watch Habuur, expressing confidence that Habuur wouldn't cross him, explaining that Girdun was used to different rules then those governing the police. Ben found Girdun and delivered Shevu's message, seeing Barit Saiy, a young Corellian he had informed on to Solo, among the prisoners Girdun was watching.

A week later, Solo returned from Corellia and found that Girdun had failed to extract any information from Habuur despite using brutal methods. Solo decided to interrogate Habuur personally, taking Ben with him. Solo used the Force to slam Habuur onto the table, prompting Ben's objection, leading Solo to send him outside. Solo continued to torture Habuur using the Force for hours, with Ben hearing her screams. Shevu and Girdun arrived, and Ben told Shevu what was happening. Shevu decided to intervene, telling Girdun they had to stop the interrogation or Habuur could die. Though hesitant, Girdun relented, and Shevu overrode the lock. Both officers entered the room, and Shevu, seeing Habuur's condition, yelled for a medic. Solo ordered Shevu out, but both officers continued their efforts to revive Habuur before concluding she was dead. Shevu confronted Solo about his actions, appearing to have no regard for Solo's power. Though Solo defended himself, Shevu insisted on reporting the prisoner's death, with Solo reacting dismissively. Girdun offered to continue his methods on the other prisoner, but Shevu objected. Solo ignored Shevu and ordered Girdun to proceed, enraging Ben.

Later, Ben sought Shevu's help in locating Barit Saiy after failing to find him among the prisoners. Shevu consulted GAG records but couldn't find Saiy. He also checked for a transfer to the CSF but found no record. Though equally concerned, Shevu cautioned Ben against personal and emotional involvement, advising him to follow procedure. When Ben pointed out Solo's disregard for rules, Shevu stated that Solo was his commanding officer. Ben acknowledged it was Shevu's way of saying he would not give an opinion on Solo's actions, but he was able to feel through the Force how angry Shevu was over Solo killing Habuur. Ben left to practice his lightsaber techniques before Solo called him, stating that the CSF reported they had a running battle occurring between Atzerri and Coruscanti in the lower levels as well as ten bomb threats. Using the maps of Galactic City, Ben was able to locate an approximate area of a serious threat.

Ben and Solo met Shevu at the landing pad next to the new GAG ships–CSF assault ships painted black–to head for quadrant H-90 to locate the threat. Shevu reported that the area was not secure and that the CSF had requested assistance from the GAG before they moved in. He stated that the incident had begun when CSF officers had arrested someone for spray painting anti-government slogans on a Galactic City Authority building and the uproar had caused a riot squad to be deployed to deal with the unruly protesters. Upon their arrival they were briefed by a CSF sergeant who said they had received a tip off that weapons were being horded but they didn't want to risk a full scale riot by going in to search. Solo offered to go in but placed the decision with Ben who was hesitant. Shevu remained supportive stating he would follow Ben in who, using the Force, was able to locate the threat inside a restaurant. Ordering them to go in, Ben led the way and the troops landed securing the entrance.

Shevu accompanied Ben inside to the kitchen, covering the young Jedi with his blaster. Admonishing him that he needed to use an earpiece, Shevu used hand signals to instruct Ben on how to open the door to the freezer where they found over a dozen shoulder missile launchers. Ben then felt the threatening presence of two individuals and he and Shevu went up to the next floor. They entered the room and Ben killed both men, even though one was not armed, sending Ben into a state of shock. Shevu, seeing Ben severely upset, argued with Solo over having such a young boy involved in police work and killing people, saying that this was too much for a boy to deal with. However Solo responded that Ben was a Jedi and learned to handle a lightsaber at a very young age. Solo then reminded Ben it had been his choice to go in and Ben had to learn to live with the consequences of his actions.

Later, Shevu attempted to locate Habuur's body so that he could file his report on her in custody death. He became increasingly upset as all records related to her had disappeared. Ben approached him, asking him if he knew where Solo was. Frustrated, Shevu replied that Solo came and went as he pleased. Though he apologized he for being snappish, he continued his search confirming with Ben that Habuur's body had disappeared as well. Shevu had received information from his colleagues at the CSF that questions had been raised about Habuur and he asked Ben if he knew who she had been. Ben stated that he did not and sensed that Shevu now seriously disliked Solo, not just his methods. Seeing that Ben was overwhelmed, Shevu sent the boy home telling him he would let him know if Solo returned.

With the crisis between the Galactic Alliance and Corellia erupting into all-out war, Shevu continued as Solo's second in command in supervising raids on Coruscant with Solo taking more and more leave from his duties as commander of the Guard to deal with political issues, feeling that Shevu was utterly reliable. Though Shevu maintained an outward appearance of loyalty towards Solo, his frustration with Solo's methods were well known to senior domestic security staff such as Gefal Keb in the Department of Public Protection and were shared by Shevu's fellow GAG troopers who were formerly from the CSF and the CSF itself. Shevu took his dislike of Solo and put it into his work by staying away from his commander and working missions with his troops such as surveillance on a weapons drop off location with Sergeant Wriut. Though Solo sensed that Shevu was not as enthusiastic about his duties as he had been to begin with several week earlier prior to the start of the war, he dismissed it since Shevu appeared to be a dedicated and hands-on commanding officer.

Several months into the war, Shevu was at a briefing with Ben at the GAG headquarters when Solo announced that the GAG would begin to focus on professional spies of the Corellian-Confederation government. Additionally, he informed the troopers that they would take over the protection details of the Chief of State and key ministers, a duty previously held by the CSF. Ben could sense the reluctance and misgivings held by Shevu and the other former CSF officers in the room. When Solo announced that they would also be tracking and monitoring senators, Shevu, though showing a calm and blank face, asked if they were even allowed to do so. Solo stated that they were and Shevu remained outwardly blank yet Ben could sense his sharp unhappiness with the situation. After the meeting, Solo pulled Ben aside, requesting him to assassinate the Confederation leader, Dur Gejjen. Ben was hesitant but agreed and Solo also ordered Shevu and Corporal–shortly thereafter Lieutenant–Jori Lekauf to accompany him.

Months after the Confederation war began, Shevu was ordered to bring Ben to Vulpter. Gejjen had been behind the plot to kill pro-Galactic Alliance Hapan Queen Mother Tenel Ka, as well as found in negotiations with Chief of State Cal Omas. After Ben completed the job, Shevu attempted to sacrifice himself to look as if a crazed spacer killed the Prime Minister instead of the GAG, though Jori Lekauf disobeyed his orders and sacrificed himself, causing Ben and Shevu grief.

After telling Lekauf's family of what happened, Shevu allowed Ben to stay at his home with him and Shula, though the stay was brief. Sometime later Shevu had heard rumors of Bothans trying to smuggle a proton bomb onto Coruscant.

When Ben approached him with the proposition of a joint investigation into Jacen Solo, who was secretly Darth Caedus, Shevu revealed that his own investigation was already underway. He also explained that Shula's absence was a precautionary measure, intended to protect her should Caedus or the GAG discover his activities. While Shevu personally favored Boba Fett's's brand of justice for Caedus, he was prepared to accept the judgment of the GA and the Jedi Council. Furthermore, Shevu acted as a double agent, providing intelligence to the Jedi. During his investigation of Caedus' StealthX, he found it necessary to delay Girdun to ensure the investigation could be completed successfully.

With the aid of a CSF Forensics droid, Shevu and Ben scrutinized Caedus's StealthX. Their examination yielded a twenty-nine centimeter long hair belonging to Mara, complete with a tag and traces of blood. This finding was subsequently verified by comparing it to a hair sample of Mara's that Luke Skywalker retained. Later, Caedus himself corroborated this evidence by confessing to Shevu that he had fought with and ultimately killed Mara Jade Skywalker. Ben then presented his recordings of the murder scene, the collected physical evidence, and a recording of Caedus's confession to his father, Han and Leia Organa Solo, and Jaina Solo on Endor.

Several weeks following the Second Battle of Fondor, Shevu convened with Ben on Coruscant, informing him of Caedus's fleet's movement towards the Roche asteroid field. During this meeting, Tahiri Veila, Caedus's Sith apprentice, and the GAG captured Shevu. Although his injuries were minor, he received no treatment, and the intent was to use his pain to coerce Ben into revealing the location of the Jedi base. When Ben remained uncooperative, Tahiri Veila employed Force lightning against Shevu, inadvertently causing his death. Shevu's final act was to instruct Ben to keep the base's location secret and to remain silent. Medical personnel attempted resuscitation, but their efforts were unsuccessful. After escaping from GAG custody, Ben arranged for Shevu's body to be returned to Shula. Shevu's death played a crucial role in Tahiri Veila's eventual redemption, as it instilled doubt in her actions and her role as a Sith.

Shevu, a man of integrity, was known for his willingness to engage in the less desirable aspects of combat. He demonstrated strong leadership qualities during the initial GAG missions, leveraging his prior experience in law enforcement to minimize GAG casualties. As a former officer in the CSF, Shevu understood the emotional toll of losing comrades in battle but also recognized the importance of prioritizing the mission.

Despite his initial loyalty to the Galactic Alliance at the start of the Second Galactic Civil War, his profound dislike for Jacen led him to become a spy for Cha Niathal before the Second Battle of Fondor. This animosity stemmed from Jacen's decision to place Ben on the front lines of the war and his treatment of Ben as an adult, despite Ben's youth. Shevu frequently attempted to shield Ben during GAG missions, even offering to sacrifice himself if Dur Gejjen's assassination attempt failed, a responsibility that Jori Lekauf ultimately fulfilled with his life. Tragically, this protective instinct ultimately led to his demise, as Tahiri exploited it by killing him in an attempt to force Ben to reveal Shedu Maad's location.

Karen Traviss created Shevu in her novel Star Wars: Legacy of the Force: Bloodlines, part of the Legacy of the Force series. His character was further developed throughout the series before Troy Denning killed him off in Legacy of the Force: Invincible, the series' final installment.