During the Second Galactic Civil War, Nelani Dinn served as a Jedi Knight within the Human species; she was a female. Early in her life, Dinn was chosen for Jedi training, where Jacen Solo instructed her for a period, ultimately leading to her promotion as a Jedi Knight. In 40 ABY, Dinn found herself stationed on Lorrd, where she crossed paths with her former instructor, Jacen Solo, and his apprentice, Ben Skywalker. Solo and Skywalker's mission was to investigate an unusual artifact discovered at Toryaz Station. Following a series of strange occurrences in Lorrd City, the trio identified Brisha Syo as the individual responsible for planting the artifact.
Syo then guided them to her residence, a mining installation located near Bimmiel, where she revealed her true identity: Lumiya, the Dark Lady of the Sith, a figure who had been absent for many years. Dinn became separated from the others and encountered the spectral form of a Sith Lord known as Darth Vectivus. After failing to provoke Dinn into attacking him, Vectivus directed her to a higher level, just as Lumiya was attempting to sway Solo to the dark side. Dinn tried to intervene, leading to a duel with Lumiya. The confrontation ended inconclusively, and Dinn then attempted to apprehend Lumiya. However, Solo, now influenced by Lumiya, turned against the young Knight, pursuing her through the mining facility with lethal intent. Solo eventually overtook Dinn, ending her life with a thrust from his lightsaber.
Born on the Outer Rim world of Lorrd, Nelani Dinn was identified by the Jedi Order and subsequently underwent training. In 33 ABY, Jacen Solo provided Dinn with instruction in lightsaber technique. Dinn was naturally shy, and developed feelings for Solo, but her lack of confidence prevented her from expressing them. However, her training, which included the task of bisecting live gundarks, significantly helped her overcome her shyness. By 40 ABY, Dinn had successfully completed the Jedi Trials and achieved the rank of Jedi Knight.
In 40 ABY, Dinn was stationed on her homeworld, Lorrd, when she received a communication from Solo, who was investigating an artifact recently unearthed at Toryaz Station. Dinn secured a contact, Dr. Heilan Rotham, who could examine the artifact, and arranged a meeting with Solo and his apprentice, Ben Skywalker, on Lorrd. The trio proceeded to Dr. Rotham's office in Lorrd City, where Dr. Rotham discovered that the artifact contained encoded messages that Dinn found foreboding. Their meeting was interrupted when Dinn received a message stating that a man in a Y-wing threatened to launch missiles into a populated area of Lorrd City unless he could speak with a Jedi. Recognizing that Dr. Rotham required time to decipher the artifact, Dinn, accompanied by Solo and Skywalker, departed to address the threat.
Dinn, Solo, and Skywalker were greeted by lieutenant Neav Samran of the Lorrd Security Force, who briefed them on the situation. The individual in the Y-wing was Ordith Huarr, a former fighter pilot who had served in the Rebel Alliance during the Galactic Civil War. Huarr claimed to be seeing the ghost of his deceased wife, but before Dinn could extract further information, Jacen Solo used the Force to forcibly bring the Y-wing down. Huarr then detonated the missiles, resulting in his own death. Following Huarr's demise, Dinn expressed her frustration with Solo, believing he could have employed more peaceful methods to resolve the conflict and prevent the loss of life. Subsequently, the group returned to Dr. Rotham, who had translated all but one of the remaining messages on the artifact.
Soon after, similar mysterious incidents involving Force ghosts began to occur frequently on Lorrd. In one instance, Dr. Movac Arisster, a professor at the University of Pangalactic Cultural Studies, took hostages inside an aquarium, strapping himself and one of the hostages to a bomb. Arisster claimed to have communicated with the late Jedi Master Aayla Secura, who instructed him to bring the Jedi to him for discussion. Arisster's sole desire was to achieve fame. He was dying of cancer and sought to defeat a Jedi to leave a lasting legacy. Arisster intended to deny the Jedi a positive outcome, preventing them from fulfilling their duty to save the hostages. Solo, realizing Arisster had succeeded, allowed him to detonate the bomb, killing himself and his captive, Serom Haxan. Dinn was angered by Solo's decision to let Arisster kill himself and Haxan without exploring alternative solutions.
Several more incidents involving Force ghosts followed, including one involving a man named Borth Pazz, who threatened to jump from a building unless he was given Jedi training. Pazz, dressed in old Jedi robes and holding an outdated, non-functional lightsaber, stood atop the building. He demanded that the Jedi teach him a Jedi trick, despite his complete lack of Force-sensitivity. When his demand was refused, Dinn watched as he jumped, his fall slowed by Solo's use of the Force. Pazz ended the day with a broken leg, and was taken away while complaining about Jedi trickery and deception. Shortly after these events, a mysterious woman named Brisha Syo arrived on Lorrd. Syo was immediately arrested upon landing at the Lorrd City Spaceport, and Solo suspected her of orchestrating the incidents involving Huarr, Arisster, and Pazz. Syo admitted to causing the events and revealed her Force-sensitivity. She also confessed to planting the artifact on Toryaz Station and offered to take Dinn, Solo, and Skywalker to her actual home, a planetoid in a star system near Bimmiel. Against the advice of Dinn and Skywalker, Solo accepted the offer to travel to Syo's home.
Dinn, Syo, Solo, and Skywalker subsequently arrived at Syo's home, a former mining outpost located on an asteroid within the MZX32905 system, near Bimmiel. Syo explained that the last administrator of the outpost, a Sith named Darth Vectivus, had abandoned the place long ago. She mentioned that Vectivus had not committed any evil acts, which Dinn doubted, and she mocked him. Syo scolded her for her ignorance, and Dinn responded with a cold smile. Dinn sensed the presence of the dark side permeating the asteroid, which Syo attributed to the original inhabitants of the outpost—a sentient species similar to mynocks. This mynock-like species was once led by a caste of Force-users, who eventually embraced the dark side. Syo then revealed the reason for bringing the Jedi to the Home, as the mynock species called it: a Sith Lord resided in the caverns, where the dark-side corruption was most potent, and Syo felt she should not confront him alone.
Dinn, Skywalker, Solo, and Syo boarded a mine car to descend into the depths of the Home, but during the descent, Syo pushed Skywalker and Dinn out of the car. Dinn and Skywalker were then ambushed by a large group of indigenous creatures, but they eventually discovered that the creatures were merely illusions, projections of the Force. Dinn was suddenly seized and pulled away from Skywalker by an unseen force, appearing before the ghost of Darth Vectivus. Vectivus challenged Dinn to kill him, revealing that he, along with all the illusions in the Home, were connected to a living being somewhere in the galaxy. Dinn refused to attack the illusion, even when Vectivus attempted to provoke her by assuming the form of Palpatine. Vectivus then instructed Dinn to climb to safety and await the arrival of the others.
Above, Syo had revealed her true identity to Solo: Lumiya, Dark Lady of the Sith. Lumiya was attempting to turn Solo to the dark side, suggesting he adopt the ways of the Sith. Jacen began to believe he could save the galaxy with the power such an allegiance would grant him. Lumiya believed that because Jacen had not been corrupted by the light side, he could resist the temptations of the dark, but just as Lumiya revealed this, Dinn appeared and interrupted the conversation. Dinn was concerned that Lumiya's words were influencing Solo, and after Lumiya suggested that Solo's former master, Vergere, had been a Sith, Dinn attacked Lumiya.
As Lumiya continued to try to sway Solo to the dark path, the two dueled, with neither gaining an advantage. Solo pleaded with them to stop, but as soon as they ceased fighting, Dinn arrested Lumiya in the name of the Galactic Federation of Free Alliances. Lumiya agreed, but Solo, wanting to learn more from Lumiya, was unwilling to allow his new mentor to be taken into Alliance custody. Having fallen under Lumiya's influence, Solo was prepared to defend the Sith, even against his former student. Convinced that the galaxy would fall if Lumiya was arrested, Solo chose his side and suddenly pursued Dinn, intending to kill her. After a chase through the Home, during which Dinn steadily lost ground to Solo, she was cornered and quickly disarmed. Dinn pleaded with Solo, not for her life, but for him to reconsider his actions and turn away from the future she foresaw for him. Nevertheless, Dinn's former mentor stabbed her in the center of the chest with his lightsaber, and the Jedi Knight died looking into the eyes of her killer.
Following Nelani Dinn's death, Lumiya promised Jacen Solo that her body would be given the proper rites befitting a noble warrior. Solo also distorted Ben Skywalker's memory of the events on the asteroid. In the following months, Skywalker, after witnessing Solo's murder of bounty hunter Ailyn Vel, decided to investigate the true circumstances of Dinn's death. After the Jedi Masters Luke Skywalker and Mara Jade Skywalker searched Lumiya's apartment, they came to believe that Brisha Syo was Lumiya's daughter and that Syo killed Dinn.
Dinn described herself as having a "shyness problem" when she began training with Jacen Solo, and her feelings for the Jedi Knight made her too self-conscious to express them. However, when they met again in 40 ABY, Dinn, having gained confidence through her Jedi training, openly expressed her feelings for Solo. Dinn was very excited when Solo and Dinn met again, but was disappointed when Solo did not return her feelings. She was idealistic and disagreed with the methods employed by Jacen Solo in the cases of Ordith Huarr and Movac Arisster. She believed that Solo could have explored more peaceful alternatives in those situations, which resulted in the deaths of both Huarr and Arisster. Because of her strong commitment to the light, she did not hesitate to attack Lumiya when the Sith attempted to turn Jacen Solo to the dark side of the Force, and she continued to try to bring Solo back to the light until her death. Before Solo killed Dinn, he saw a glimpse of her potential future, which included love and a family. She had black hair.
Nelani Dinn possessed a strong attunement to the emotional states of others, as demonstrated when she sensed the anxiety of lieutenant Neav Samran. Dinn was skilled in telekinesis, which she used to maneuver in low-gravity areas of the Home. She was able to sense the host connected to the phantom of Darth Vectivus, initially mistaking that being's dark side aura for Vectivus' own. She also felt the Sith Lord's Force exertion when he used it to illuminate the exit from the caverns for her. She moved at incredible speed during duels, but she was not fast enough to overcome Lumiya, who repeatedly evaded Dinn's attacks before retaliating. Despite her own skill, Dinn lacked experience against opponents wielding lightwhips and was overwhelmed by Lumiya's unusual weapon. Her dueling abilities were also inferior to those of Jacen Solo, who defeated Dinn in combat and killed her with minimal effort.
Dinn carried a lightsaber with a yellow-white blade and received training in its use as a Padawan under Jedi Knight Jacen Solo.
The character of Nelani Dinn was created by author Aaron Allston for his 2006 novel Betrayal, the first book in the Star Wars: Legacy of the Force series. In the novel, Dinn mentions that Solo taught her lightsaber technique seven years before the events of Betrayal, which takes place in 40 ABY. However, this would place the time she was his pupil during the five years that Solo spent away from the Jedi Order. Allston noted in his blog that other dating inconsistencies in the novel were due to the novel originally being set in 37 ABY and later revised without all mentions of timeframe being fixed.