Wilyem, belonging to the male gender, was a Barabel individual who achieved the rank of Jedi Knight within the New Jedi Order. During the events of 43.5 ABY, Wilyem collaborated with his fellow Barabel Jedi, Zal and Dordi, as they accompanied Captain Han Solo in a mission to create a distraction for the Galactic Alliance forces. This allowed Solo's wife, Leia Organa Solo, to discreetly transport four psychotic Jedi away from the planet, preventing their capture by the Galactic Alliance. Throughout this operation, Wilyem took on the role of a gunner, stationed at the tail section of the Millennium Falcon. Subsequently, in 44 ABY, Wilyem, along with Zal, Dordi, and Tesar, the son of Dordi and Sebatyne, established a concealed nest within the Jedi Temple. Shortly thereafter, the Jedi Order departed from the planet Coruscant as part of a strategic maneuver to lure the Lost Tribe of Sith into a carefully planned trap. However, the Barabels remained behind, safeguarding their nest. As the Jedi executed their trap, the Sith retreated into the Temple, and Allana Solo—Han and Leia Solo's granddaughter, who had previously stumbled upon the Barabel nest—experienced a Force vision indicating an impending attack on the nest. Consequently, the Solos journeyed back to Coruscant and engaged in combat with the Sith within the Temple to alert Wilyem and the other Barabels. The Barabels were successfully evacuated from the Temple, along with their younglings, aboard the Parting Gift, which was piloted by Jagged Fel, the former Head of State of the ex-Imperial faction.
Wilyem, a Barabel of the male persuasion, exhibited sensitivity to the Force. He underwent training in the ways of the Force as a member of the New Jedi Order, ultimately achieving the esteemed rank of Jedi Knight. During the period of 43.5 ABY, a perplexing mental affliction began to manifest within several young Jedi Knights, leading them to believe that their acquaintances had been replaced by impostors. The Galactic Federation of Free Alliances resolved to address this issue by incarcerating the afflicted Jedi Knights within carbonite. However, the Jedi Order expressed disapproval of this action and secretly concealed as many of the ailing Knights as possible within the New Jedi Temple situated on the galactic capital planet of Coruscant for further investigation. To thwart Galactic Alliance Security forces from discovering these Jedi and encasing them in carbonite, Captain Han Solo and his spouse, Leia Organa Solo, devised a plan to smuggle the Jedi offworld. Wilyem, alongside fellow Barabel Jedi Knights Dordi and Zal, served as gunners for Han Solo and his granddaughter, Allana Solo, aboard the Millennium Falcon. Their mission was to orchestrate a diversion for Galactic Alliance forces positioned in orbit above Coruscant while Organa Solo discreetly transported the four Jedi who had been apprehended by the Order—Seff Hellin, Natua Wan, Yaqeel Saav'etu, and Bazel Warv—to Shedu Maad within the Hapes Cluster.
The Millennium Falcon flagrantly disregarded established departure protocols, thereby attracting the attention of the Galactic Alliance Nargi-class pursuit frigate, known as the Fast Death. Following their failure to heed the Fast Death's warnings, they were subsequently engaged by Bolt Squadron, a unit composed of XJ5 X-wing starfighters. Solo piloted the Millennium Falcon behind PharmCom Orbital Processing Plant One, a pharmaceutical manufacturing facility situated in orbit above Coruscant, while the Fast Death remained behind, to be substituted by another pursuit frigate, the Quick End. Solo then instructed Allana to notify Jedi Master Saba Sebatyne and proceeded to direct Dordi and Zal to activate their weaponry and targeting systems as a feint. He further stipulated that only Wilyem was authorized to discharge his weapon, albeit with the caveat that he was prohibited from hitting anything.
Subsequently, Master Sebatyne arrived accompanied by a squadron of StealthXs and targeted Bolt Squadron. Concurrently, acting upon Solo's directives, Wilyem launched a proton torpedo from the aft docking bay. The torpedo detonated a few kilometers behind them, and Solo feigned that they had sustained a hull breach resulting from a Galactic Alliance torpedo. As he maneuvered the Millennium Falcon in a corkscrew trajectory toward the Quick End, feigning a loss of control, he disclosed to the Quick End's command that he had Allana—disguised as his adopted daughter "Amelia"—on board. The Quick End, finally persuaded that Solo was not engaging in deception, maneuvered out of his path and terminated all Galactic Alliance pursuit as Solo instructed Allana to utilize the Force to reach out to Organa Solo, who discreetly smuggled the four Jedi Knights offworld aboard the Gizer Gut. Wilyem, the Solos, Dordi, and Zal then initiated a jump into hyperspace to rendezvous with the Jedi at Shedu Maad.
In 44 ABY, Wilyem initiated the construction of a nest concealed within the underlevels of the Jedi Temple in collaboration with Zal, as well as Dordi and Tesar Sebatyne. This nest was inadvertently discovered by Amelia and her companion, Jedi Knight Bazel Warv, one of the Jedi whom Wilyem had previously assisted in smuggling offworld, and who had since recovered and returned to Coruscant. The Barabels insisted that the two individuals remain at the nest until their eggs hatched, ensuring their continued concealment and the safety of their eggs. However, Amelia proposed an exchange of secrets—she disclosed the truth of her identity, revealing herself as Allana, the daughter of the Jedi Jacen Solo and Queen Mother Tenel Ka Djo, and the heir to the Hapan throne. The Barabels acknowledged that the secret possessed sufficient significance and permitted Amelia and Warv to depart.
Shortly thereafter, the Jedi resolved to evacuate the planet in an attempt to lure the emerging Lost Tribe of Sith into a carefully orchestrated trap. Wilyem and the three other nesting Barabels remained behind; however, when the Jedi decided to spring their trap and assail the Sith, the Tribe retreated into the Temple. Concurrently, Allana experienced a vision depicting the killing of the Barabels' younglings, prompting her to return to Coruscant and locate the nest—accompanied by her grandparents, the Jedi Knight Zekk, the hapan Taryn Zel, and several Hapan commandos— to warn them about her vision. Wilyem initially exhibited caution, but the trespassers revealed that they had intended to drop off Warv to caution them, but they had been ambushed and Warv had been killed.
Subsequently, the Barabels returned to the nest to gather their younglings and then fought their way out of the Temple, eliminating several Sith along the way—although numerous commandos and some of the younglings also perished. They were then met by the former Imperial Remnant Head of State Jagged Fel in the Parting Gift, along with Master Saba Sebatyne, former Jedi Knight Tahiri Veila, and Sergeant Major Gef Olazon. Wilyem, Dordi, Zal, Tesar, and their younglings—of whom twenty remained—were all safely extracted from the Temple.
Being a Barabel, Wilyem possessed a specific sense of humor common to his species, which was often misunderstood by other beings. Much of the conversation between the crew of the Millennium Falcon was interpreted as humor among the three Barabel Jedi, who maintained their high spirits throughout the mission, even when faced with potential difficulties. Upon Amelia and Warv's discovery of the Barabel nest, Wilyem and the other Barabels expressed outrage and resolved to compel the two to remain until their eggs hatched. When Amelia voiced her concern that her adoptive mother would reprimand her—figuratively—Wilyem responded sincerely that it would be preferable for Organa Solo to kill her than for him to do so. Like other Barabels, Wilyem was fiercely protective of his nest and asserted that he would never permit anyone to consume their eggs. When Amelia proposed her exchange of secrets and informed the Barabels that revealing her secret would likely result in her death within a year, Wilyem and the others accepted the terms and allowed the two intruders to depart. Wilyem was initially distrustful of Allana when she returned with additional trespassers, but after she provided an explanation, Wilyem took her vision with utmost seriousness.
Wilyem acquired knowledge of the light side of the Force within the Jedi Order and successfully completed his training, ascending to the rank of Jedi Knight. He was a skilled gunner and was the only one of the three Barabel Jedi Knights whom Solo authorized to open fire during their mission to smuggle the Jedi offworld.
The character of Wilyem was conceived by author Troy Denning for his 2009 novel, Fate of the Jedi: Abyss, which served as his inaugural installment and the third book overall in the nine-part Fate of the Jedi series. He subsequently made brief appearances in Fate of the Jedi: Vortex and Fate of the Jedi: Apocalypse, the sixth and ninth novels in the series, also penned by Denning.