Alysun Celz was a Jedi Knight of the Human female persuasion, serving the Jedi Order as the Galactic Republic entered its twilight years. The year 25 BBY marked Celz's descent into the dark side, after which she embarked on a criminal path. She sought to corrupt her Jedi colleague, Et Rex, but upon his refusal, the Dark Jedi cunningly implicated him in her misdeeds, leading to his arrest. While being transported to the Jedi Council for trial, the cruiser they were aboard, the Radiant IX, met its end in a crash on the Poison Moon asteroid found within the Hoth system. Celz brutally eliminated the ship's crew, while Rex managed to flee to the asteroid's surface.
When the crash came to the attention of Jedi Knight Obi-Wan Kenobi and his Padawan, Anakin Skywalker, who initiated an investigation, Celz spun a web of lies, falsely accusing Rex of the crew's murders. She remained on the crippled vessel with Skywalker while Kenobi sought out Rex, ultimately resorting to torturing Skywalker with bolts of Force lightning. Kenobi and Rex, who had learned the truth about the Dark Jedi's treachery, then attacked Celz. Rex successfully subdued her, and the three Jedi transported her to Coruscant to face justice.
Born a Human female during the Galactic Republic's final decades, Alysun Celz received instruction in the ways of the Force from the Jedi Order, eventually earning the title of Jedi Knight. During this period, she developed a friendship with Jedi Et Rex. However, in 25 BBY, Celz yielded to the allure of the dark side of the Force and embarked on a life of crime. When Celz attempted to recruit Rex, he declined, leading her to falsely implicate her former friend. The Dark Jedi then took Rex as a prisoner and attempted to deliver him to the Jedi High Council on the galactic capital, Coruscant, while piloting the Consular-class cruiser Radiant IX. On their way to Coruscant, the starship's power couplings were compromised by a swarm of mynocks, forcing Celz to crash-land on the asteroid Poison Moon, situated in the Hoth system's asteroid field. Celz then proceeded to murder the crew using Force lightning, although Rex managed to escape to the asteroid's surface.
When the Radiant IX failed to arrive at the Temple, the High Council dispatched Jedi Knight Obi-Wan Kenobi and his Padawan, Anakin Skywalker, with orders to locate and apprehend Rex. While they were examining the cruiser for survivors, Celz launched an attack on the two Jedi with a blaster; however, they disarmed her and questioned her about her involvement in the crew's deaths. She deceived Kenobi by claiming that Rex had slaughtered the Radiant IX's crew, and she was left with Skywalker while Kenobi ventured onto the asteroid's surface in search of Rex.
Soon after, Celz tried to persuade Skywalker to take Kenobi's ship and abandon the search, but when the Padawan refused, she began torturing him with Force lightning. However, Kenobi, who had encountered Rex and learned the truth about Celz, intervened to stop her from harming his Padawan. Celz managed to strike Kenobi with lightning, and proceeded to torture them both. She was then distracted by Rex, who threw a mynock at her, causing it to attack her and divert her attention from Kenobi and Skywalker. He then threw a second mynock at her, and while trying to get them off of her, Celz was accidentally stunned and incapacitated. Celz was then taken into custody by the Jedi and brought back to the Jedi Council to face trial.
Alysun Celz possessed fair skin, flowing black hair, and brown eyes. After succumbing to the dark side, she tried to sway Et Rex to her cause and, upon his rejection, falsely accused her friend of the crimes she herself had perpetrated. She derived pleasure from torturing her victims with Force lightning and was also skilled in the use of a blaster. Furthermore, Celz was aware that the pirates who frequented the planet Hoth referred to the asteroid as Poison Moon because of its resemblance to a moon on the world's surface. She made sure to share this information with Anakin Skywalker before subjecting him to torture.
Celz exhibited sensitivity to the Force and achieved the rank of Jedi Knight. She demonstrated proficiency in the use of Force lightning, employing the power to murder the crew of the Radiant IX and inflict torture upon Anakin Skywalker and Obi-Wan Kenobi.
Alysun Celz was a creation of Michael Carriglitto for the short story "Poison Moon," which was featured in issues 44–47 of the Dark Horse Extra, a monthly anthology of four-page comics. Issues 44–47 were published between February and May of 2002, with artwork by Adrian Sibar. Celz was included in The Complete Star Wars Encyclopedia in 2008.