Hosk Trey'lis, a Jedi Knight and healer hailing from the Bothan species, and identified as male, participated in the Ossus Project. This initiative, undertaken by the Jedi, aimed to utilize Yuuzhan Vong technology to terraform planets devastated during their invasion of the galaxy. The One Sith, in league with the Fel Empire, sabotaged the project in 127 ABY, triggering a war between the Empire and the Alliance. Trey'lis successfully evaded the massacre that decimated the Jedi Order on Ossus at the close of the Sith-Imperial War, subsequently spending seven years as a fugitive. In 137 ABY, while awaiting transport offworld in Brogar's on the planet Lok, Cade Skywalker, a former Jedi turned bounty hunter, along with fellow hunters Jariah Syn and Deliah Blue, stormed into the cantina with the intention of capturing Naxy Screeger, a gambler. Mistaking the hunters' target, Trey'lis attempted to escape, believing himself to be their quarry. Recognizing the Bothan's Jedi nature, the hunters apprehended Trey'lis and delivered him to the Sith to collect the bounty placed on Jedi.
Within the Temple of the Sith located on Coruscant, the galactic capital, Darth Maladi, the leader of Sith Intelligence and Assassination, subjected Trey'lis to torture and interrogation. Ultimately, Trey'lis succumbed to her brutal methods and revealed all he knew about Skywalker, whose healing abilities were desired by Darth Krayt, the Emperor and Dark Lord of the Sith. After receiving a vision of the Bothan, Skywalker journeyed to Coruscant to rescue Trey'lis, only to be captured himself. A week later, after feigning allegiance to Krayt and undergoing training as a Sith, Skywalker attempted another rescue, but was again unsuccessful. Both Trey'lis and Skywalker were brought before Krayt in his chambers, where the Dark Lord sought to coerce Skywalker into killing the Bothan as a demonstration of his loyalty to the Sith. Trey'lis, unwilling to be used as a tool, implored Skywalker to resist the allure of the dark side. Krayt then struck down the Bothan, causing Trey'lis's body to vanish as he became one with the Force.
Hosk Trey'lis, a male Bothan, served as a Jedi Knight and healer, collaborating with Jedi Master Kol Skywalker on the Galactic Alliance-sponsored Ossus Project. This project aimed to employ the Yuuzhan Vong in the terraforming of worlds ravaged by their invasion of the galaxy. However, in 127 ABY, the emergent One Sith Order, allied with the Fel Empire, sabotaged the project, igniting a war between the Empire and the Alliance. Despite the massacre of the Jedi Order on Ossus at the conclusion of the Sith-Imperial War, Trey'lis avoided death while many other Jedi were killed. As the deposed Emperor-in-exile Roan Fel initiated his insurgency against the Sith-controlled Empire, Trey'lis went into hiding, spending the next seven years on the run, during which he lost his lightsaber in an explosion from which he barely escaped.
In 137 ABY, Trey'lis found himself in Brogar's, a secure haven and cantina located on the planet Lok, where he had arranged transportation off-world. While awaiting his departure, Cade Skywalker, a bounty hunter and former Jedi, along with his associates Jariah Syn and Deliah Blue, suddenly entered the cantina in pursuit of Naxy Screeger, a gambler wanted for outstanding debts. Mistaking the hunters' intentions, Trey'lis employed the Force to hurl a table at them. Recognizing the opportunity to claim the larger bounty placed on Jedi, Syn targeted Trey'lis, while Skywalker continued to pursue Screeger.
To prevent the Jedi's escape, Syn prepared to shoot Trey'lis, but Skywalker intervened by throwing Screeger into Syn's back, causing him to drop his blaster. Blue opted for a different approach, attempting to incapacitate Trey'lis with a tranquilizer dart fired from her dart launcher. However, Trey'lis remained unaffected by the attack and unleashed a surge of Force energy, sending Blue flying backward. Ultimately, Trey'lis was subdued by an illegal thud bug thrown by Syn, rendering the Bothan unconscious. En route to the bounty hunters' ship, Trey'lis pleaded for his release, emphasizing that the Sith's treatment would be far worse than death. Skywalker and his companions remained unmoved, proceeding to collect their bounty.
Upon arriving at Socorro, the bounty hunters attempted to deliver Trey'lis and Screeger to the Crimson Axe, an old starship repurposed as a stationary base of operations for the pirate Rav. However, Trey'lis managed to break free and flee. Skywalker pursued the Bothan, following him as he jumped off a ledge. During their fall, Trey'lis recognized the Force's power within Skywalker, realizing it was not influenced by Sith training. After plunging into the water below, Trey'lis was rescued by Skywalker and brought before Rav, who had been observing the encounter via a holovid recorded by his droids. Rewarding Skywalker, Blue, and Syn for their efforts, Rav ordered his crew to take Trey'lis and Screeger away. After receiving hallucinogenic death sticks from Rav, Skywalker was visited by the spirit of his ancestor, the renowned Jedi Grand Master Luke Skywalker. Luke pointed out that Cade had never turned a Jedi over to the authorities before, and attempted to dissuade his descendant from taking the death sticks, which deadened his connection to the Force. Cade disregarded his ancestor's advice and forced him to leave by threatening to take his own life.
Having been handed over to the Sith in exchange for the bounty on living Jedi, Trey'lis was imprisoned in the laboratory of Darth Maladi, the head of Sith Intelligence and Assassination. Seeking information about Skywalker, whom the reigning Dark Lord of the Sith, Emperor Darth Krayt, desired for his healing abilities, Maladi subjected the Bothan Jedi Knight to interrogation and torture. Trey'lis was unable to withstand Maladi's ruthless methods and eventually revealed everything he knew about Skywalker, including his Force abilities and the identities of his companions, Jariah Syn and Deliah Blue. Using the information gleaned from Trey'lis, Maladi instructed intelligence agent Nyna Calixte to personally oversee the search for Skywalker and ensure his capture alive.
While Skywalker was on Ossus, completing his Jedi training, he experienced a vision of Trey'lis during one of his meditations. During this vision, Cade was visited once again by his ancestor Luke Skywalker. Instead of trying to convince Cade of his duty to the Jedi, Luke told Cade that the Sith were torturing Trey'lis on Coruscant, and it was his responsibility to make it right. Despite not having completed his training, Cade left Ossus and headed to Coruscant to rescue Trey'lis. Meanwhile, in the Sith Temple on Coruscant, Trey'lis was forced to use his healing abilities on Krayt, who was struggling to control the Yuuzhan Vong implants—gained during the Yuuzhan Vong War—which threatened to take over his body. His abilities proved inadequate, however, and Krayt continued to seek Skywalker.
Upon arriving on Coruscant and infiltrating the Sith Temple, Skywalker located the laboratory where Trey'lis was being held. As Skywalker freed him, Trey'lis sought forgiveness for succumbing to the Sith's interrogation and revealing information about the former Jedi. During their escape, Trey'lis attempted to explain his betrayal, but Skywalker refused to listen. Sensing imminent danger, Skywalker used the Force to push Trey'lis out of the way just as they were attacked by one of Krayt's personal assassins, his Hand, Darth Talon. Engaging the Sith in a brief duel, Skywalker was overpowered when Krayt's other Hand, Darth Nihl, joined the fight. After capturing the former Jedi, the two Hands delivered Skywalker to their Master, while Trey'lis was returned to Maladi's laboratory.
Following Skywalker's failed rescue attempt, Trey'lis remained imprisoned in the laboratory for a week, while Skywalker feigned allegiance to Krayt and underwent training as a Sith. Meanwhile, Skywalker's friends, aided by his mother, Imperial Moff Nyna Calixte, planned to rescue him from the Sith from within the underlevels of Coruscant. Nyna was acting under the guise of her alter ego, Morrigan Corde, in order to hide her true identity. After being held in the Yuuzhan Vong torture device known as the Embrace of Pain, Skywalker attempted another escape and returned to Maladi's lab to rescue Trey'lis. Expecting such an attempt, Talon had been waiting in the lab, and the former Jedi was once again captured. Taken to Krayt's chambers, Skywalker was berated by the Dark Lord of the Sith, who ordered him to kill Trey'lis to demonstrate his loyalty to the Sith. Knowing that Krayt wanted him alive, Skywalker refused, stating that Krayt's threats were meaningless. In response Krayt commanded that Trey'lis be killed, which angered Skywalker as he did not want the Bothan to die for him. Not wanting Krayt to use him as weapon, Trey'lis pleaded with Skywalker to resist Krayt's temptations of the dark side. Prepared to die, the Bothan told Krayt that he forgave Skywalker, and that he pitied the Dark Lord. Drawing his lightsaber, Krayt struck the Bothan down, and Trey'lis's body disappeared, becoming one with the Force.
The voice of Trey'lis's spirit spoke to Skywalker, telling him the Force would be with him. Enraged at the murder of Trey'lis, Skywalker prepared to attack Krayt when he was visited by the spirit of his father, Jedi Master Kol Skywalker, who advised Cade to use the Force to break into the case that held his father's lightsaber—taken by the Sith after Kol's death on Ossus. Skywalker engaged Krayt and his two Hands in a short duel. Both Nihl and Talon were injured, and Skywalker escaped through a hole blasted in the wall by his mother, Nyna Calixte, who had arrived to rescue him.
Hosk Trey'lis was a male Bothan with brown fur and brown eyes. Unlike many Bothans, who held political scheming and spying in high regard, Trey'lis valued healing, patience, and communion with the Force. Peaceful by nature, Trey'lis preferred to practice the healing arts over the ways of the warrior. As a Jedi, the Bothan strove to be a force of good in the galaxy, even after the Jedi were decimated at the end of the Sith-Imperial War. Despite his inherent peaceful nature, Trey'lis was willing to fight for his survival when pursued by Skywalker and his fellow bounty hunters. Unwilling to surrender without a fight, Trey'lis even attempted a last minute escape while constrained in binders.
Although the Bothan did not fear death, Trey'lis implored Skywalker and his friends to let him go rather than turn him over to the Sith, knowing what the Sith could do to him would be far worse. While being tortured by Darth Maladi, Trey'lis was initially able to resist the interrogation; however, Maladi's methods eventually proved too much for the Bothan, and his will broke, leading him to tell the Sith all he knew about Skywalker.
Trey'lis did not hold grudges against those who wronged him, quickly forgiving Skywalker when he came to rescue the Bothan from the Sith Temple. Trey'lis also felt guilty for giving the Sith information on Skywalker during his interrogation, believing he had betrayed the former Jedi. When Krayt threatened the Bothan's life in an attempt to turn Skywalker to the dark side, Trey'lis pleaded with Skywalker not to let them use him as a weapon. Knowing his death was imminent, Trey'lis was not afraid; instead, he found a greater happiness and a deeper sense of peace than he had ever felt before. Trey'lis even forgave Krayt, pitying the Dark Lord and the man he once was. At peace, Trey'lis's body vanished as Krayt dealt the killing blow, and the Bothan became a Force spirit.
Aside from his talents as a Jedi and healer, Trey'lis was also multilingual, able to speak Bocce, Bothese, and Yuuzhan Vong, in addition to Basic.
As a Jedi Knight, Hosk Trey'lis was skilled in the use of the Force, particularly in the arts of healing. Like most Jedi, Trey'lis was trained in the use of a lightsaber, and used it before losing it in an explosion. He was proficient in telekinetic applications of the Force, able to throw both objects and people with powerful waves of energy, as he showed during his attempted escape from Skywalker and his friends. Despite being restricted by binders, Trey'lis showed that he was skilled in unarmed combat, able to put up a fight against Skywalker, Blue, and Syn as they attempted to turn him over for the bounty on living Jedi.
Although he was capable of combative uses of the Force, Trey'lis's true talent was as a healer rather than as a warrior. He was able to sense the emotions of individuals through the Force, and was able to sense that something was emotionally broken within Skywalker. Forced to use his healing abilities on Darth Krayt, Trey'lis's powers proved inadequate in combating the Yuuzhan Vong implants, which threatened to take over the Dark Lord's body. A peaceful healer to the end, Trey'lis's body disappeared upon his death, and he became a Force spirit.
The initial mention of Hosk Trey'lis occurred in the introductory supplement to the Star Wars: Legacy comic series, specifically Star Wars: Legacy (2006) 0, which was released in June 2006. In this publication, his last name was initially spelled Tre'lyis. Subsequently, his name was corrected to Trey'lis in the expanded version of the supplement, Star Wars: Legacy (2006) 0½. Trey'lis later appeared in the second issue of the series, titled Broken, Part 2, which was released in July 2006. This issue was authored by John Ostrander and Jan Duursema, with Duursema also providing the pencil work. Trey'lis's storyline was further developed throughout the series until his demise in the eighteenth issue, titled Claws of the Dragon, Part 5. Trey'lis's backstory was later elaborated upon in the Legacy Era Campaign Guide, a sourcebook for the Star Wars Roleplaying Game Saga Edition released in March 2009. Additionally, he was included in The Complete Star Wars Encyclopedia. In the 113th edition of Star Wars Insider, Trey'lis's death was featured on the list 5 Evil Deeds! (Expanded Universe), which ranked the five most heinous acts in the Star Wars Expanded Universe.