A human male named Lux Bonteri, hailing from Onderon, served as a senator and rebel fighter during the Clone Wars. He was the offspring of Separatist senator Mina Bonteri. During the era of the Clone Wars, he forged alliances with Saw and Steela Gerrera, jointly spearheading the Onderon rebels throughout the Onderonian Civil War. Following the conclusion of that conflict, he emulated his mother's path and became a senator himself, this time representing Onderon in the Republic. In the subsequent Imperial Era, Bonteri reconnected with Saw, who was at the helm of the Partisan rebel faction, and eventually became a member of the Dreamers after Saw's demise.
Lux Bonteri was the son of Onderon's senator, Mina Bonteri, and her husband. At the tender age of four, he delighted in vibrant hues and creative messes, which manifested in paintings, including one depicting a speeder bike. His mother cherished these creations, keeping the speeder bike painting in her office within the Galactic Senate Building even as Lux's interests evolved. In 28 BBY, Padmé Amidala noticed these artworks during a tea gathering with Mina in her office.
Following the establishment of the Confederacy of Independent Systems, Bonteri and his family aligned with the Separatists when Onderon embraced the Confederacy of Independent Systems. The Bonteri family relocated to Raxus Secundus, the Confederacy's capital, where his mother held a position in the Separatist Senate. Sometime after Onderon's allegiance shifted, Bonteri's father, an officer within the Confederacy military, tragically died during the establishment of a base on Aargonar following an attack by Republic clone troopers early in the Clone Wars.

During the Clone Wars period, Bonteri was present when Republic Senator Padmé Amidala and Jedi Padawan Ahsoka Tano journeyed to Raxus to engage in discussions with his mother regarding the prospect of brokering a peace treaty between the Confederacy and the Republic. While his mother and Amidala engaged in negotiations, Bonteri and Tano engaged in conversation outdoors in the garden. Both individuals articulated their prejudiced viewpoints regarding the war; Bonteri voiced his skepticism of the Jedi and the Republic, while Tano expressed her distrust of the Separatists. Bonteri's encounter with Ahsoka marked his first interaction with a Jedi, while Ahsoka had never previously encountered a Separatist civilian. They both came to the realization that they were not so different from one another. Despite their allegiance to opposing factions in the war, the pair swiftly formed a friendship.
Following her discussion with Amidala, Mina Bonteri initiated a motion within the Separatist Senate to commence peace negotiations with the Republic Senate. The vote garnered majority support, prompting Amidala and Tano to return to Coruscant. However, Count Dooku, the Separatist Head of State and secretly a Sith Lord, sought to perpetuate the war for the benefit of the Sith. Dooku orchestrated a Separatist attack on Coruscant, which swayed the Republic Senate to vote against peace negotiations with the Separatists. Furthermore, Dooku covertly ordered the assassination of Mina Bonteri, publicly attributing her death to the Republic. The tragic loss of his mother left Lux orphaned, and he staunchly refused to accept the Republic's culpability in her demise.
Convinced that Dooku was responsible for his mother's death, Bonteri sought out the Mandalorian Death Watch, led by former Separatist ally Pre Vizsla. Vizsla, like Bonteri, harbored a desire for retribution against Dooku following Death Watch's failed attempt to seize control of Mandalore, which resulted in Dooku withdrawing his support from the organization. Together, Bonteri and Vizsla devised a plan to locate Dooku using a holotrace device, after which Death Watch would aid Bonteri in assassinating Dooku.

During a peace conference between the Confederacy and the Republic on Mandalore, a neutral system, Bonteri disrupted the meeting by making an uninvited entrance and publicly accusing Dooku of his mother's murder. This caused alarm among those in attendance, including Republic Senator Padmé Amidala and Jedi Padawan Ahsoka Tano, who was serving as Amidala's personal bodyguard. Separatist Congress Leader Bec Lawise ordered Bonteri's arrest, and security droids escorted him from the room. The droids brought Bonteri before Dooku via hologram, where Bonteri subtly activated his holotrace device to ascertain the location of Dooku's transmission. Dooku, oblivious to Bonteri's actions, denied any involvement in Mina Bonteri's death and decreed that Bonteri should be executed for treason. Before the droids could carry out the execution, Ahsoka intervened, rescuing Bonteri after having followed him from the meeting. Tano, accompanied by R2-D2, escorted Bonteri to the Phoenix, where she contacted Jedi Knight Anakin Skywalker, who instructed her to bring Bonteri to Coruscant. Bonteri refused, asserting his intention to confront Dooku with the assistance of Death Watch. Upon learning of his desire to kill Dooku, Tano cautioned him against it and began to steer the Phoenix toward Coruscant. However, Bonteri, resolute in his decision, incapacitated Tano, concealed her lightsabers, and transported her to Carlac to rendezvous with Death Watch.

Upon arriving on Carlac, Bonteri intended to meet with Death Watch alone, leaving Tano on the ship. However, upon awakening, Tano instructed R2 to retrieve her lightsabers and safeguard them, enabling her to conceal her true identity from Death Watch. Just as Tano caught up with Bonteri outside their ship, the pair was greeted by Bo-Katan Kryze, Pre Vizsla's second-in-command, who escorted them to the Death Watch camp to meet with Vizsla. Tano, feigning engagement to Bonteri, cautioned him against trusting Death Watch due to their terrorist ideology, but Bonteri disregarded her warnings. When brought before Vizsla, Bonteri provided him with the holotrace device, and Vizsla invited Bonteri to a celebratory feast. Bonteri accepted, and the celebration ensued with Tano serving as a servant, alongside several Ming Po women who had been captured by Death Watch. The celebration was interrupted when Chieftain Pieter of the nearby Ming Po village demanded that Vizsla return the captured women.

Surprisingly, Vizsla acquiesced, promising Pieter that he would return the women to the village the following day. Bonteri interpreted this as a sign of honor and integrity within Death Watch, dismissing Tano's earlier warnings. However, the truth was unveiled when Vizsla and his soldiers returned the women to the village, only to murder Pieter's granddaughter Tryla in front of him and proceed to raze the village. With the innocent Ming Po in peril, Tano revealed her true identity as a Jedi when she attacked the Death Watch soldiers to protect the Ming Po people, leading to her capture by Death Watch.
Bonteri and Tano were taken prisoner by Death Watch, and Bonteri realized that Tano had been right when Lux saw that Vizsla planned to execute Tano for the Jedi's crimes against Mandalore. However, R2-D2 entered the tent and created a distraction, allowing Bonteri to escape while Tano engaged Vizsla in lightsaber combat. Outside the tent, Bonteri discovered many battle droids that the Death Watch had been using for target practice turn on their masters after being reassembled by R2. With the droids' assistance, Tano and Bonteri were able to escape the Death Watch on the Phoenix. Tano again wanted to take Bonteri to Coruscant, but Bonteri again refused, headed toward the ship's escape pod. Tano tried to stop him, but Bonteri said he needed to find his own way, hoping that they would see each other again. Departing on good terms, Bonteri detached the pod and left Tano to go into hiding.

Eventually, Bonteri returned to his homeworld of Onderon, which was under Separatist occupation. The Separatist regime had made Sanjay Rash King of Onderon, and removed the true King, Ramsis Dendup. Bonteri joined a resistance group that had been formed by Steela and Saw Gerrera with the goal of returning Dendup to the throne. In order for their mission to be successful, however, the rebels required supplies, weapons, and training. Using his personal connection to Ahsoka Tano to his advantage, Bonteri contacted the Jedi High Council, asking for aid to help restore peace to Onderon. The Jedi promised to help, however many were resistant to becoming directly involved in the matter, saying that it was an internal affair and out of their control. Jedi Knight Anakin Skywalker suggested that the Jedi provide supplies and training to the rebels, but not directly become involved in the fight; allowing the rebels to retake their homeworld on their own. Agreeing with this idea, the Council sent Jedi Generals Obi-Wan Kenobi and Anakin Skywalker, accompanied by Commander Ahsoka Tano and Clone Captain CT-7567, known as "Rex," to Onderon where they began to train the rebels for combat.
Upon arrival to Onderon, Kenobi, Skywalker, Tano, and Rex were brought to the rebel camp and began to train the rebels. The rebels began by learning to disable Armored Assault Tanks and droidekas using grenades. Bonteri was particularly good as disarming the droidekas, however when paired with Saw to take out the tank, he fell off the tank taking Saw down with him. This caused Saw to be upset with Bonteri, claiming that he was a politician and not meant to fight. Both Steela and Saw could not disable the droidekas, and Steela became frustrated with herself, preferring her skills as a sniper to destroy droids.
While practicing their marksmanship with the Jedi, a group of battle droids, learning the location of the rebel base, began to attack the rebels. Using their new training, the rebels took out the first wave of battle droids using grenades. However, the second wave of battle droids arrived with a tank, which Bonteri and Saw had been unsuccessful disarming in training. Bonteri and Saw paired up again to take out the tank, and this time succeeded, using thermal detonators and destroying the tank. After succeeding in defending their base, the Jedi and the rebels decided that they were ready to take the fight to Iziz and reclaim Onderon. In order to get into the Separatist controlled city, Bonteri came up with the idea of posing as hunters, coming back into Iziz to sell their game in the market. Not detecting any of their weaponry due to the high amounts of organic matter on their carts, the battle droids allowed the rebels to enter. After entering Iziz, the group split up to avoid attention; agreeing to regroup after nightfall.

The group decided to execute a series of small strikes on battle droid battalions throughout the city, where Bonteri hid behind a market stand and disables a patrol of droids in front of some citizens. When the rebels later met up in a safehouse in Iziz, Saw suggested that they increase their attacks on the Separatists. However, it was noted that many of the civilians in Iziz had become frightened by the sudden outbreak of violence, and it was suggested by Bonteri and Steela that they first must win the trust of the people. Bonteri suggested that they take on a large target to show their strength and draw public attention to themselves. It was decided that they would attack the city power generator. Skywalker, Kenobi, and Rex left the rebels and returned to Coruscant, while Tano remained as an advisor to the rebels.
Eventually, after some time training, Bonteri, Tano and the Onderon rebels—led by Steela—made their presence known to the people in Iziz and fought against the droid army, forcing them to retreat. Onderon was won, Dendup became king again, and Bonteri—having his faith placed in the Jedi and the Republic—was appointed Senator of Onderon. He swore to serve the Republic.
Following the rise of the Galactic Empire, Bonteri entered into matrimony with an Imperial woman and assumed the role of father to her daughter. Both Bonteri's wife and stepdaughter held unwavering allegiance to the Empire. Bonteri's goddaughter Maia became a member of Saw Gerrera's Partisans and met her demise during a mission to the Mid Rim planet Inusagi. Bonteri subsequently joined the ranks of the Rebel Alliance.
Subsequent to Saw's death during the destruction of Jedha City, Bonteri reached out to his stepdaughter, conveying his profound distress over Saw's passing. He requested amnesty from his stepdaughter, who worked in a clerical position, in exchange for surrendering to the Empire and divulging all information pertaining to the Rebel Alliance and their operations. Bonteri's stepdaughter, deeply fond of him, provided him with specific times and locations where he could surrender himself to moderate Imperial authorities who could be trusted to honor his defection without resorting to torture or execution. However, instead of surrendering, Lux contacted Staven, the leader of the Dreamers, and joined the group as "the Mentor". Bonteri gradually shared the information obtained from his stepdaughter, providing Staven with a continuous stream of Imperial targets.
Staven frequently clashed with the Mentor, but refrained from killing Bonteri due to his exclusive access to the targeting information acquired from his stepdaughter. Despite aligning with the extremist Dreamers, Bonteri opposed attacks on civilians. Bonteri vehemently protested when Staven and Sadori Vushan sought to bomb a munitions factory while teenage students were touring, but was overruled by other Dreamers who viewed Imperial schoolchildren as enemies-in-training.

When Imperial Captain Iden Versio, who had infiltrated the Dreamers along with her special forces team members, confronted Bonteri, he recounted his life story and the circumstances surrounding his acquisition of the target list from his stepdaughter. She had discovered that he had loved both a Jedi and a freedom fighter, as well as much more of his history. Iden inquired whether he had ever contemplated surrendering himself, to which he admitted he had, but he feared that the Empire would eventually trace the source of his information to his stepdaughter and subject her to torture and/or execution—a prospect he could not bear. When Versio revealed her intention to kill Bonteri in order to recover the stolen information in his possession, he implored Versio to always have hope before she shot him. Instead of killing Bonteri, Versio stunned him, but after she went back to collect him his body was no where to be found, leaving her to question his whereabouts.

With his family joining the Confederacy of Independent Systems, Lux initially sided with the Separatists when the Clone Wars began. Before the war, Lux heard that the Jedi were good, but as they fought for the Republic that the Separatists saw as corrupt, Lux was left not knowing what to think about the Jedi, hearing things contrary to what he had heard about them from several people, including his friends. Although Lux had never met a Jedi, that changed when her mother was visited by her friend Padme Amidala, who was accompanied by Jedi Padawan Ahsoka Tano. Despite their differing opinions about the war and the sides they both represented, Lux and Ahsoka immediately became friends, which improved Lux's opinion of the Jedi.
After the death of his mother, who was murdered by Count Dooku due to her efforts to end the war, Lux decided to get revenge on Dooku, and began working with Death Watch. However, after seeing Death Watch destroy and massacre a village and try to kill Ahsoka because she was a Jedi, Lux regretted joining the group, as although they both wanted Dooku dead, Lux realized they were just assassins just like Dooku. After seeing how his homeworld, Onderon, was suffering from Separatist occupation, Lux joined the rebels led by Steela and Saw Gerrera to liberate the world.
After the rise of the Galactic Empire, Bonteri married a woman and ended up joining the Alliance to Restore the Republic. Learning of Saw Gerrera's death during the war against the Empire greatly upset Lux, which made him use information he got by lying to his stepdaughter about surrendering to the Empire to help the Dreamers attack various Imperial targets. Although the Empire was his enemy, Bonteri was against risking the lives of imperial civilians. When confronted by Iden Versio, an imperial captain, Bonteri said he couldn't turn himself in because he knew the Empire could trace the source of information to his stepdaughter, and Bonteri couldn't bear to think about what the Empire could do to her, showing concern with her. Lux was infatuated with Ahsoka Tano and Steela Gerrera, a Jedi and a freedom fighter, which was said in his confrontation with Versio.