Ngaaluh, a Yuuzhan Vong priestess of the deception sect, was a female and a devout worshiper of the goddess Yun-Harla for the majority of her existence. However, during the time of the Yuuzhan Vong War, her faith in the True Way was undermined by Vergere, a Jedi of the Fosh species, who was a subject of interrogation. The priestess secretly held onto her newfound heresy, developing her own ideas and eventually embracing a strong belief in the Force and its potential impact on the journey of her species.
Upon discovering a clandestine heretical cult functioning deep within the conquered world of Coruscant, Ngaaluh journeyed to encounter Yu'shaa, the Prophet who spearheaded the movement. Leveraging her respected position, she became his informant within the court of Supreme Overlord Shimrra Jamaane. Ngaaluh recognized the Prophet as Nom Anor, the disgraced executor, but unlike many others, she was convinced that Anor was acting in the best interests of his followers. In reality, Nom Anor manipulated Ngaaluh for his personal advantage, using her to frame, discredit, and eliminate his adversaries within the Intendant caste. Sadly for the deceitful priestess, Shimrra grew suspicious of her unusual success in exposing numerous traitors and initiated an investigation into her activities. When the Supreme Overlord confronted her in his court, Ngaaluh ingested poison and died to serve the Jeedai heresy. Despite her demise, the movement persevered and played a role in the downfall of the Yuuzhan Vong Empire during the Battle of Yuuzhan'tar.
Ngaaluh was known to be closely associated with Harrar, another member of the deception sect, and she was often seen with the elder priest in the court of Supreme Overlord Shimrra. In the later part of 26 ABY, before the Battle of Yag'Dhul, Harrar sent Ngaaluh to his acquaintance, Warmaster Tsavong Lah. Ngaaluh informed the warmaster about the return of Vergere, a Fosh who had been associated with deception sect priestesses Falung and Elan. Vergere had vanished after the failure of Elan's mission to assassinate the Jedi, and Ngaaluh oversaw the interrogation of the enigmatic being within the haar vhinic, a device commonly utilized by the Yuuzhan Vong to extract the truth from prisoners. During the interrogation, however, the Fosh challenged her questioner's belief in the True Way and the Great Doctrine. Ngaaluh became convinced that the religion promoted by the priests was a sham, and that the Supreme Overlord and the priests could no longer be trusted as the intermediaries to the gods. She continued to contemplate these matters internally, even after Vergere was returned to Tsavong Lah. Eventually, the priestess attempted to reconcile the existence of the Force with that of the True Way. She remained confused in many aspects, knowing only that she was willing to sacrifice her life to serve the Force, which she believed to be a lingering breath of the great god Yun-Yuuzhan, and those who wielded it—the Jedi.
Subsequently, Ngaaluh collaborated with Vergere and the rebellious Master Shaper Mezhan Kwaad to devise a plan to overthrow the Yuuzhan Vong religion and caste system. In 27 ABY, she journeyed to the moon Yavin 4 alongside Vergere, where they supervised the torture of Tahiri Veila, a captured Jedi whom Mezhan Kwaad intended to mold into a devoted servant of the Yuuzhan Vong.
Being a follower of Yun-Harla, Ngaaluh possessed significant expertise in subterfuge and intelligence, making it easy for her to locate the heretical movement thriving in the lower levels of the reshaped planet Coruscant. Displaying genuine piety, Ngaaluh successfully passed the screening conducted by the Shamed Ones and integrated herself among the heretics. Yu'shaa, the Prophet of the movement, was delivering a sermon that Ngaaluh observed intently, becoming increasingly certain that this religious leader, concealed by an ooglith masquer, was Nom Anor, a disgraced member of the Intendant caste who had been forced into hiding following the disaster at Ebaq 9. Ngaaluh was also disguised, her slender form hidden within a masquer that gave her a scarred and grotesque appearance. However, as she questioned Anor—forcing him to delve deep into his repertoire of rhetoric and deceitful truths—the executor realized that he was facing a highly intelligent and articulate Yuuzhan Vong, disguised like himself and with unknown intentions. Ngaaluh demanded to know the Prophet's plans and how the movement would advance further. Nom Anor detected the fiery doubt and desire for purpose in her eyes and believed that she could be useful. However, Ngaaluh soon disrupted the gathering by continuing to question his doctrine. When Anor realized that this acolyte might be the spy he had been searching for, he beckoned Ngaaluh to approach. However, the priestess shocked him by revealing that she knew his identity. Unfortunately for Ngaaluh, Anor was extremely paranoid at the time, and when she reached inside her simple robe to offer him an unrik, he fired his plaeryin bol from his eye socket, spitting lethal poison into her face. The moment the executor discovered her true identity and the potential uses of the priestess, he administered the antidote. Anor instructed his aides, Kunra and Shoon-mi Esh, to take the faithful priestess to a safe set of quarters and provide her with the best possible care. There, she gradually regained her strength and pledged allegiance to Nom Anor as the leader of the heresy. Despite being wary of the possibility that Ngaaluh was a double agent, Anor decided to use her as a source of much-needed intelligence on Shimrra.
Equipped with a villip, Ngaaluh returned to the court of Supreme Overlord Shimrra. Due to her position, the deception priestess was granted relatively high-level access to the Great Council of the Yuuzhan Vong. However, on her first visit to the court in this new role, Ngaaluh had to request her superior, Harrar, to grant her access to the throne room. There, she delivered intelligence on Yu'shaa, claiming to possess knowledge of the Prophet and his motives. Shimrra was enraged by Ngaaluh's announcement and questioned her about the desires of the heretics. However, the Dread Lord's fury subsided, and he was left to contemplate the implications of this growing heresy. Ngaaluh was permitted to act as an "inquisitor" of sorts, rooting out heresy for the Supreme Overlord and providing him with victims to cast into the yargh'un pits.
Shimrra soon appointed the priestess as the leader of the movement responsible for investigating corruption and heresy across Yuuzhan'tar. With a large number of assistants—who remained unaware of her true agenda unless they were also heretics—Ngaaluh gained a formidable reputation among the intendants who oversaw the administration of Yuuzhan'tar. Nom Anor had targeted several of his old rivals in the intendant caste for destruction and unleashed Ngaaluh upon them, knowing that in her new role as Shimrra's inquisitor, she would be able to have the unfortunate intendants removed and killed. The deception priestess served Anor with unwavering loyalty, convinced that Nom Anor believed in the tenets of the heresy as much as she did, and willingly accepted her first assignment: an investigation into the affairs of Prefect Ash'ett of the Vishtu Sector. Ash'ett was an old enemy from Anor's early days in the intendant caste, and while Ngaaluh viewed the framing and discrediting of the Prefect as an opportunity to install a loyal heretic in his place, Anor relished the chance for revenge. Ngaaluh and Anor planted heretic Shamed Ones within Ash'ett's command structure and then had them "uncovered" by loyal Yuuzhan Vong.
Once the fabricated evidence had been gathered, Ngaaluh presented five of the captured heretics before Shimrra and embarrassed High Prefect Drathul, a hated enemy of Anor's, by casting aspersions on the intendant caste and Prefect Ash'ett. Both Anor and Ngaaluh were satisfied with the outcome. Ash'ett was executed along with every member of his immediate family, and Drathul and the entire intendant caste suddenly fell under suspicion, much to Anor's delight. Meanwhile, Ngaaluh continued her work tirelessly, thrilled at the opportunity to practice the tenets of the heresy and the Jeedai by eliminating corruption among the intendants and furthering their cause. Soon, Prefect Drosh Khalii of the Geling Sector, another of Anor's former rivals, was executed based on evidence planted by Ngaaluh. However, the priestess began to worry that the Prophet's tactics—the gradual removal of lowly intendants and executors—were insufficient to overthrow Shimrra. Unfortunately for Ngaaluh, she never realized that Anor's goals differed significantly from those he professed as the leader of the heresy. Nevertheless, the priestess launched a campaign against another of Nom Anor's enemies, Prefect Zareb of the Numesh Sector, and planned to deliver her incriminating evidence to the court.
Shimrra, however, was not easily fooled. Upon the sudden revelation that two of his Prefects were heretics, he began conducting his own investigations—not into the heresy, but into Ngaaluh herself, who remained unaware of what was happening. Although Shimrra had executed the second Prefect, Drosh Khalii, he had personally interrogated the heretics planted by Ngaaluh in the Prefect's sector. Confronted with the Supreme Overlord's wrathful presence, the Shamed Ones broke and revealed the truth about their missions. Thus, when Ngaaluh delivered her intelligence on Prefect Zareb, Shimrra was prepared. Thanking the priestess for her discoveries, the Supreme Overlord descended from the polyp throne and walked among the Elite, questioning Warmaster Nas Choka, High Prefect Drathul, Master Shaper Yal Phaath, and High Priest Jakan in turn. Eventually, having instilled a weighty sense of fear among his subordinates, Shimrra turned to Drathul, proclaiming that a heretic had infiltrated the highest echelons of his empire. Ngaaluh, mesmerized like everyone else by the spectacle of a doomed High Prefect, failed to notice in time that the guards approaching to restrain Drathul were, in fact, encircling her. Trembling, the priestess could only watch as the massive figure of the Supreme Overlord stalked towards her. Shimrra denounced the priestess as a fraud, although he did not conclude that she was a heretic herself, only that she had falsely incriminated several loyal supporters and was working for the Prophet. Before he could question her further, Ngaaluh momentarily broke free, just long enough to ingest poison and die in front of the assembled mass of shocked Yuuzhan Vong. On Shimrra's orders, guards dragged her lifeless body from the throne room and threw the corpse onto the piles of dead in a yargh'un pit. Nom Anor watched the darkening scene through the villip for some time, transfixed by the sudden reversal of his fortunes.
Ngaaluh's heresy shocked Shimrra's court and sparked considerable doubt about the Supreme Overlord's tenure and his status as a conduit to the gods. It proved that the heresy was not limited to the Shamed Ones and the workers but had, in fact, spread to the highest levels of government. Shimrra became extremely vigilant about spies, and frequent sweeps of the lower levels of Yuuzhan'tar were conducted to root out the heresy. Shamed Ones were removed from positions where they might harm the Yuuzhan Vong Empire, and the Supreme Overlord was forced to reaffirm his position by creating the Slayers. He also tolerated the presence of the Royal Seers among his entourage to appease his followers. For Nom Anor, Ngaaluh's death was unsettling. It demonstrated that his movement remained vulnerable, and instead of feeling triumphant at the apparent weakening of Shimrra's position, the executor concluded that the Supreme Overlord remained as strong as ever and that he would soon join her in the yargh'un pits. The loss of his spy in Shimrra's court forced him to adopt new tactics, and he began spreading rumors that a living planet would lead the heretics to salvation. In fact, the stories of Zonama Sekot had been shared with him by the deceased priestess, and he twisted them to maintain his hold on power, as his movement was failing to grow any further. Ngaaluh's fanaticism had also made an impression on Kunra, Anor's loyal agent, and the Shamed One would later prevent Nom Anor from abandoning his role as Prophet during the last battle of the war.
Ngaaluh was a fanatic who vowed to give her life for the movement she so passionately believed in, and she ultimately fulfilled that oath. Her intelligence and acumen were fitting for her role as a priestess of deception, and the fact that she could lie without showing fear in the face of the Supreme Overlord himself demonstrated considerable courage. However, the zeal with which the priestess pursued her heresy allowed her to become a tool for Nom Anor's purposes. Ngaaluh was naïve in her belief that Anor, a cunning and devious individual, had become a devoted religious leader. Essentially, Ngaaluh's training as a deception priestess contrasted with her impressionability and naïveté, and this combination of character traits significantly contributed to her death.
Ngaaluh first appeared in The New Jedi Order: Edge of Victory II: Rebirth as an associate of Harrar tasked with interrogating Vergere, an enigmatic figure in The New Jedi Order series. In The New Jedi Order: Force Heretic II: Refugee, it was revealed that Ngaaluh had been corrupted by Vergere during this period, and she joined Nom Anor's heretical movement. By the time of her death towards the end of the final novel in the Force Heretic trilogy, Ngaaluh had become a character of reasonably high importance, in terms of her relationship with Anor and the insights she allowed him to gain into the inner workings of the Yuuzhan Vong Empire.