Shimrra Jamaane

Born into Domain Jamaane many decades prior to the Battle of Yavin, Shimrra was a male Yuuzhan Vong. The Yuuzhan Vong, an extra-galactic species, had journeyed through the Intergalactic Void for countless years, seeking a new galaxy after devastating much of their original home galaxy in an internal war. As adherents of the True Way, their religious belief system, the Yuuzhan Vong were deeply devout, worshiping various gods, with Yun-Yuuzhan, the creator god, as their principal deity. Yuuzhan Vong society was structured into castes, including the Supreme Overlord, warriors, intendants, priests, shapers, workers, and Shamed Ones. Due to their reliance on their gods, the Yuuzhan Vong placed significant importance on their priests and their god-king, the Supreme Overlord. The Supreme Overlord alone possessed a connection to Yun-Yuuzhan, and all other Yuuzhan Vong were entirely subservient to him.

Shimrra had a twin brother; such a birth was a rarity, only the third instance of twins in their species' history. In the previous two cases, one twin had killed the other, subsequently leading the Yuuzhan Vong during periods of crisis. Consequently, due to his twin status and noble lineage, Shimrra was included in a select group of candidates for the position of Supreme Overlord. As a candidate, Shimrra enjoyed numerous privileges and received training in both warfare and religion. Shapers enhanced his growth, resulting in an exceptional size. At the age of seven, Shimrra eliminated his brother to remove a potential rival for the throne, displaying early signs of aggression and ruthlessness.

After many fruitless years traversing space, the Yuuzhan Vong discovered a galaxy and initiated scouting operations. In 32 BBY, Supreme Commander Zho Krazhmir, dispatched by Supreme Overlord Quoreal to explore the galaxy, found the planet Zonama Sekot within the new galaxy. Zonama Sekot was a sentient planet, bearing many similarities to the species' original homeworld, Yuuzhan'tar. Ancient legends foretold of a living planet that would bring about the Yuuzhan Vong's destruction. Thus, upon being informed of this discovery in 29 BBY, Quoreal chose to continue their journey in search of another galaxy. This decision made him unpopular, particularly among Domain Jamaane.

At this juncture, Onimi, a disgraced former shaper, decided to intervene. Onimi had previously discovered that the eighth cortex—the final level of Shaping protocols, dispensed directly by the gods and accessible only to the Supreme Overlord—was empty, contrary to established belief. Upon this discovery, Onimi concluded that the Yuuzhan Vong were doomed without the ability to adapt. He attempted to graft yammosk tissue onto his brain, but the experiment resulted in physical deformation, leading to his designation as a Shamed One and the loss of his rank. However, it also opened him up to the Force, from which the Yuuzhan Vong had been severed millennia prior. Onimi believed that after millennia of travel through the void, the Yuuzhan Vong would annihilate themselves without an enemy to focus their energies upon. Furthermore, he sought to usurp the gods' position and believed that conquering a new home would elevate the Yuuzhan Vong to the same level as the gods.

Utilizing his powers, he instructed Shimrra to accept him as his familiar and jester. Onimi gained control of Shimrra, who then initiated a coup to seize the throne. With the support of numerous warriors, Shimrra successfully overthrew and killed Quoreal. He then executed many of Quoreal's most ardent supporters, along with the other candidates for Supreme Overlord, to consolidate his power. He also suppressed all knowledge of Zonama Sekot. Having accomplished this, the new Supreme Overlord announced to his people the discovery of a new galaxy, claiming it had been revealed to him in a dream from the gods. However, before the Yuuzhan Vong could claim the galaxy, they would have to defeat the countless beings already inhabiting it. The Yuuzhan Vong considered them infidels for not worshiping their gods and for using machine technology, which was despised by followers of the True Way. Thus, before the Yuuzhan Vong would settle in the new galaxy, all infidels would have to be killed or converted, and their technology destroyed. Though not all members of the species supported Shimrra and his decisions, the dissidents remained silent, knowing that opposition would result in death. Meanwhile, as Onimi's power grew, less of Shimrra's original personality remained. However, the fact that Onimi was more than just Shimrra's jester remained a secret known only to Onimi, the true power behind the throne.

After decades of preparation, the Yuuzhan Vong launched their invasion of the galaxy in 25 ABY. The ensuing war began favorably, with the Yuuzhan Vong catching the New Republic completely unprepared. Hesitant to engage in all-out war, the New Republic focused on defending major hyperlanes leading to the Core Worlds and the Colonies, while the Yuuzhan Vong made significant advances in the war's initial six months. Under the command of Warmaster Tsavong Lah, they captured several planets, such as Obroa-skai and Ord Mantell, shocking the galaxy with their brutality. With the galaxy in turmoil, the Yuuzhan Vong continued to gain ground over the next two years. In 26 ABY, they captured Yavin 4, home of the Jedi Praxeum, and penetrated the Core, taking the planet Duro.

In that year, Onimi discovered the heretical shaper Nen Yim. Yim operated outside normal Shaping protocols, which usually would have led to her death. However, Onimi brought her before Shimrra, who declared that she would serve him, secretly creating new techniques to fill the eighth cortex, thus providing their species with new shaper techniques. In 27 ABY, Warmaster Lah initiated Battle Plan Coruscant, aimed at seizing control of Coruscant, the galactic capital. The Yuuzhan Vong defeated the New Republic in the Battle of Coruscant, taking over the planet and leaving the New Republic reeling. The New Republic later attacked Obroa-skai, believing Shimrra was visiting the planet. Though the New Republic was victorious, they discovered that the fleet they had attacked was led not by the Supreme Overlord, but by Supreme Commander Komm Karsh.

In 28 ABY, Shimrra arrived at Coruscant in his flagship, a specialized Koros-Strohna worldship. With tens of thousands of Yuuzhan Vong assembled to cheer their leader, the ship landed. The ship became Shimrra's Citadel, housing the Supreme Overlord's throne room. Shortly after landing on the planet—now renamed Yuuzhan'tar, after their original homeworld—Shimrra held a meeting in his throne room with the Elite, the leaders of the four main castes. He reprimanded Tsavong Lah for the heavy Yuuzhan Vong casualties suffered in taking Coruscant and for failing to adapt to new New Republic techniques. He also questioned Executor Nom Anor, an advance spy, about the government of the galaxy's other beings, finding their tolerance and democracy foolish. After interrogating Anor, he spoke with Master Shaper Ch'Gang Hool, who was directing the terraforming of the planet. The effort had been replete with failures, and when Hool confessed, a furious Shimrra ordered his execution.

Soon after this meeting, Shimrra attended a ceremony dedicating a temple to the creator god Yun-Yuuzhan. The Yuuzhan Vong planned to execute over a hundred captives from the Battle of Coruscant, many of them senators or military officers. However, before the ceremony could begin, the Square of Sacrifice was filled with waste rejected by the maw luur, creatures that disposed of sewage. Angered, Shimrra declared the ritual invalid and ordered the captives killed without onlookers. He then held a meeting in the temple with the Elite, scolding them and questioning if the World Brain—the creature in charge of the terraforming—was behind the failures. After ordering a shaper killed for the ceremony's failure, he agreed to let Lah attack the New Republic soon.

At some point, the Supreme Overlord met alone with Nom Anor regarding the New Republic's movements and the Peace Brigade, a group of beings native to the galaxy that had allied with the Yuuzhan Vong, hoping to be on the winning side. Anor also brought news of Thrackan Sal-Solo, a Corellian politician who had promised to sign a treaty of neutrality and disable the Centerpoint Station superweapon if the Yuuzhan Vong left the Corellian system alone. Sal-Solo, along with his bodyguard Darjeelai Swan, had come to meet with Shimrra. An interrogation of Swan revealed that the New Republic, not Sal-Solo, controlled Centerpoint Station. This deception greatly angered Shimrra, though he agreed to meet with the Human.

Sal-Solo was ushered into the chamber, where Shimrra informed him that he had decided to accept the Human's offer, but had altered the deal. The Yuuzhan Vong would help Sal-Solo's Centerpoint Party take control of the Corellian system, after which Shimrra would be in charge. In addition, the Yuuzhan Vong planned not to send Sal-Solo back to the Corellian system, but to make him leader of the Peace Brigade on their headquarters of Ylesia. The galaxy's citizens saw the Peace Brigaders as traitors, and Shimrra knew that by forcing Sal-Solo to associate with them, the Human would be discredited and kept under the Yuuzhan Vong's thumb. When informed of the changes, Sal-Solo tried to negotiate his way out, but his speech only angered the Supreme Overlord. Infuriated by the fact that someone he saw as scum would attempt to speak to him as an equal, Shimrra ordered Sal-Solo removed from his chambers to be sent to Ylesia.

The Supreme Overlord later held a meeting with Anor and Lah in his private chamber. Anor had collected evidence indicating that the New Republic had fled to the Deep Core moon of Ebaq 9, and the three planned a surprise attack that Anor felt would break the back of the New Republic. However, the battle was a trap created by the New Republic, resulting in Tsavong Lah's death. After the battle, Shimrra met with the Elite in his throne room and informed them that the defeat was merely a test from the gods. Swearing revenge, he also proclaimed Nom Anor a traitor, placing a death sentence on his head. Around this time, Shimrra began to slip from Onimi's control, as the Shamed One grew preoccupied with the Trickster Goddess Yun-Harla, whom he blamed for ruining him.

Following the Battle of Ebaq 9, the war continued to worsen for the Yuuzhan Vong. As Nen Yim's efforts to develop new Shaping protocols continued to fail, Shimrra grew increasingly angered. This was partly due to the recent Jeedai heresy led by the prophet Yu'shaa, secretly Nom Anor in disguise. The Jeedai heresy was a rapidly growing movement of Shamed Ones that worshiped the Jedi as their saviors and condemned Shimrra as the "Rainbow-Eyed Enemy," the being who kept them enslaved. Around this time, Shimrra received a report from Commander Ekh'm Val. Val had discovered a mysterious planet and brought back a starship from that world with Yuuzhan Vong vessel characteristics. After hearing details of the living planet, Shimrra knew it was Zonama Sekot. Seeking to prevent others from learning of the planet's existence, he had Val killed, his name removed from the records, and his vessel, the Noble Sacrifice, destroyed, successfully keeping his power secure.

Much to the Supreme Overlord's displeasure, Yu'shaa remained at large in the Coruscant Underworld, and the heresy continued to grow. Several members of his court, such as Prefects Ash'ett and Drosh Khalii, were found guilty of heresy, as several members of their household were believers in the Jeedai movement. On this evidence, a furious Shimrra had the Prefects and their families killed. However, the evidence had been planted by the Priestess Ngaaluh, a secret follower of Yu'shaa. Nom Anor sought revenge and had arranged their downfall, as Ash'ett and Khalii were innocent. Unbeknownst to Ngaaluh and Anor, Shimrra was suspicious of the evidence, believing it too perfect.

The Supreme Overlord began his own investigations and interrogated the Yuuzhan Vong heretics planted in the Prefects' homes. When confronted, the terrified heretics confessed they had merely been placed there, effectively absolving the Prefects. When Ngaaluh accused Prefect Zareb of heresy and presented the evidence before the Elite, Shimrra questioned the caste leaders. After intimidating several of the most powerful beings in the Yuuzhan Vong Empire, Shimrra turned on Ngaaluh, revealing he had learned she fabricated the evidence and ordering his guards to seize her. However, the Priestess committed suicide by poison before they could stop her.

Shimrra refused to restore the dead Prefects' honor, claiming they would serve as a reminder to those who opposed him. The Jeedai heresy, he swore, would be stopped, and its members killed. Later, Onimi showed Nen Yim the starship brought to the Supreme Overlord by Ekh'm Val. The ship was of Sekotan origin, and while examining it, Nen Yim discovered it had similarities to the Yuuzhan Vong's yorik-et fighters. When Yim revealed her discovery to Shimrra, he ordered her to develop weapons against such vessels if the Yuuzhan Vong ever encountered them in battle. Despite seeking weapons against similar ships, he stated that the planet where the ship had come from had been destroyed, wishing to keep knowledge of Zonama Sekot from spreading among his people.

Shortly after Nen Yim began studying the ship, she fled from Shimrra's Citadel with the help of several Jedi and dissident Yuuzhan Vong. In her absence, Shimrra promoted Shaper Adept Qelah Kwaad to Master Shaper. During his questioning of Kwaad, she stated that she believed Master Shaper Ahsi Yim, who had assisted Nen Yim, had played a part in Nen Yim's disappearance. An irate Shimrra then had Ahsi Yim killed. Not long after this, he received a message from intendant Phaa Anor, who informed the Supreme Overlord that he had been contacted by Nom Anor, who had crucial information for Shimrra.

Shimrra communicated with Nom Anor through a villip, at which point the former Executor revealed his location: Zonama Sekot, alongside Nen Yim and the Priest Harrar. Shimrra scoffed at the notion, declaring Zonama Sekot's destruction impossible. Anor countered by suggesting he contact Harrar, confident that the Supreme Overlord couldn't find him on Yuuzhan'tar. Shimrra, realizing his deception was exposed and that others among the Yuuzhan Vong now knew about Zonama Sekot, felt a surge of fear. Nom Anor then proposed using his villip as a tracking device, enabling Shimrra to dispatch a fleet to obliterate the planet. Despite knowing the difficulty of destroying Zonama Sekot, Shimrra hesitated. However, Nom Anor's promise to sabotage the planet, ensuring its destruction by the Yuuzhan Vong, swayed the Supreme Overlord. If Anor succeeded, Shimrra—unaware of Anor's Yu'shaa status—vowed to pardon the former Executor and welcome him back into his court.

Ushk Choka captained the Red Qurang, tasked with retrieving Nom Anor to Yuuzhan'tar. Before Choka's arrival, Anor carried out his promised sabotage; however, his attempts failed to obliterate Zonama Sekot. Oblivious to this, Shimrra elevated Anor to the rank of Prefect. Simultaneously, rumors reached the Supreme Overlord from his spies: the tide of the war had turned, causing many Yuuzhan Vong to lose faith in him, believing he had lost the favor of their deities. Determined to crush any seeds of rebellion, he convened a meeting with the Elite, warning the high-ranking Yuuzhan Vong about the consequences of disloyalty, while also blaming them for the recent defeats, accusing them of betraying him and, by extension, the gods. Throughout the Supreme Overlord's tirade against the Elite, Onimi remained by his side, reciting rhymes as was his habit.

After concluding his lecture to his subordinates, Shimrra unveiled his ten Slayers, warriors outfitted with specialized weaponry and biot technology. Their fusion of priest and warrior castes led to their being viewed with disdain by others in his court, who denounced them as abominations. When Supreme Commander Chaan questioned the wisdom of Shimrra's creation of the Slayers, the Supreme Overlord commanded him to select ten warriors to face the Slayers in combat. To the astonishment of the assembled crowd, two Slayers triumphed over Chaan and his ten warriors.

Following the public demonstration, Shimrra held a private discussion with Nom Anor, revealing his conviction that the Yuuzhan Vong's true adversary was not the Galactic Federation of Free Alliances—the new name for the New Republic—but the gods themselves. The Supreme Overlord believed the deities had grown resentful because the Yuuzhan Vong no longer required them. In Shimrra's estimation, the Yuuzhan Vong had become sufficiently powerful to thrive independently of their gods, even to seize their power. Those who genuinely believed in the gods—the majority of Yuuzhan Vong—represented a threat to Shimrra's designs to usurp the gods' power, though he remained confident in his ability to manipulate others and advance his own agenda. However, by this point, he was utterly insane, his mind warped by Onimi's visions of power and his own animosity towards the gods.

Three days after the Battle of Caluula, which resulted in the capture of thousands of infidels, a gathering of Yuuzhan Vong, including the Supreme Overlord, took place at the Place of Sacrifice on Yuuzhan'tar for the ceremonial execution of the prisoners. However, before the ritual could commence, the Yuuzhan Vong found themselves under attack by a swarm of Shamed Ones, who managed to liberate several captives. This incident, indicative of the growing strength of the Jeedai heresy, enraged Shimrra, as the movement posed a threat to his authority. He ordered the roundup and execution of three thousand Shamed Ones in the following days, regardless of their involvement in the heresy. At some stage, he succeeded in persuading the wayward World Brain to perform its duties diligently, rather than sabotaging various projects under its direction. Consequently, the terraforming of Yuuzhan'tar finally progressed smoothly.

Shimrra subsequently directed Nas Choka to assault Mon Calamari, the new headquarters of the Galactic Alliance. Despite Choka's reservations about such an attack, the Supreme Overlord insisted that it was necessary to appease the bloodthirsty gods, particularly Yun-Yuuzhan. Three days later, a fleet under Choka's command departed from Yuuzhan'tar. Shimrra and the Elite witnessed its departure, with the Supreme Overlord imploring Yun-Yuuzhan to assist the fleet in its mission to destroy the infidels on Mon Calamari. By this juncture, Shimrra had become despised by many, who had lost all faith in his leadership and believed that the gods had abandoned him.

The Yuuzhan Vong initiated their assault on Mon Calamari and gained an advantage over the Galactic Alliance fleet, only for Zonama Sekot to suddenly materialize in the sky above Yuuzhan'tar. Nas Choka ordered a retreat to Yuuzhan'tar, instructing the Yuuzhan Vong ships already present to resist attacking the strange planet. The unexpected arrival of Zonama Sekot—proclaimed by Yu'shaa as the key to Shimrra's downfall and the salvation of the Shamed Ones—unleashed chaos on Yuuzhan'tar. Jubilant Shamed Ones rioted, while many high-ranking Yuuzhan Vong were gripped by fear and bewilderment.

After the planet remained in orbit near Yuuzhan'tar for several days, Shimrra summoned Nom Anor for a private audience. While the Prefect admitted his earlier failure to destroy the world, Shimrra declared that he did not blame Anor—instead, he attributed the event to the gods. As he explained to Anor, the Supreme Overlord believed that the gods had intervened to save Zonama Sekot and bring it to Yuuzhan'tar. He asserted that if they could now destroy it, the Yuuzhan Vong would secure victory in the war. To prevent divine intervention, Shimrra instructed Anor to inform all priests to cease worshiping any deity except the Trickster, Yun-Harla. He reasoned that focusing all their rituals on her would inflate Yun-Harla's ego, provoking the jealous gods to attack her, triggering a conflict among themselves. Shimrra envisioned this as retribution for the suffering the gods had inflicted upon the Yuuzhan Vong during their voyage through the Intergalactic Void, and he believed that while the gods were embroiled in conflict, the Yuuzhan Vong could destroy Zonama Sekot.

Later, Shimrra convened with the Elite, and after deriding them for their cowardice, he revealed that he was aware of the rumors questioning his fitness to rule. Furthermore, Shimrra disclosed his knowledge of Zonama Sekot, whose existence he had previously denied, and claimed that following his coup, he had dispatched forces to search for Zonama Sekot. However, since they had been unable to locate the legendary living world, Shimrra stated that he had begun to doubt its existence, considering it a mere fabrication of Quoreal's, born out of cowardice. He now believed that the appearance of Zonama Sekot was merely a final trial imposed by the gods. Shimrra also asserted that his prayers to Yun-Harla had yielded a solution.

During a brief engagement with Galactic Alliance forces on Caluula just days prior, all Yuuzhan Vong and their biots on the planet—along with several other life-forms—had fallen ill and perished. Shimrra concluded that this was the result of a chemical weapon developed by the Alliance. One ship had managed to return to Yuuzhan'tar, where it was quarantined in the atmosphere to prevent further infections. The Supreme Overlord intended to crash the ship onto Zonama Sekot, releasing the pathogen, infecting the planet, and ultimately killing it. Shortly thereafter, an armada led by Choka was dispatched to Zonama Sekot with the objective of infecting the planet.

Shimrra's meditation was interrupted by Supreme Commander Laait, who informed the Supreme Overlord that Nas Choka had a message for him. A Galactic Alliance fleet had positioned itself between the Yuuzhan Vong and Zonama Sekot, and although Choka's forces had breached the enemy lines, Zonama Sekot had launched its own defenses—living ships. This revelation stunned Shimrra and all the Yuuzhan Vong present. When several priests questioned Shimrra's judgment, the Supreme Overlord had his Slayers execute them, fearing further erosion of his tenuous grip on power. Responding to the speculations of High Prefect Drathul and High Priest Jakan, he proclaimed that the heretics were responsible for the appearance of these infidel vessels.

To resolve the matter, Shimrra placed half of the warriors in his Citadel under Nom Anor's command, tasking him with executing every heretic on Yuuzhan'tar. Fearing defeat, the Supreme Overlord also managed to persuade the World Brain to ignite fires across Yuuzhan'tar's surface, hoping to render it uninhabitable. Meanwhile, the Battle of Yuuzhan'tar raged on, with Galactic Alliance vessels engaging Yuuzhan Vong ships above Yuuzhan'tar. Simultaneously, the Yuuzhan Vong attempted to crash the infected vessel onto Zonama Sekot, which was currently in-system near the planet Muscave.

A contingent of Galactic Alliance soldiers and Jedi managed to land on Yuuzhan'tar, and three Jedi successfully infiltrated the Yuuzhan Vong's defenses and entered Shimrra's Citadel. In his private chambers with Onimi and fifteen Slayers, Shimrra awaited their arrival, concealing in his robes the lightsaber of the Jedi Anakin Solo, who had perished during the Mission to Myrkr two years prior. Soon, the trio reached Shimrra's private dwelling. There, the Jedi—Luke Skywalker, Jacen Solo, and Jaina Solo—engaged the Slayers in combat.

Despite Onimi's manipulation of the Citadel, constantly disrupting everyone's balance, the Slayers were unable to overcome the Jedi, with Luke Skywalker displaying particular ferocity. Shimrra soon joined the fray, wielding his Scepter of Power, a unique amphistaff. He engaged Skywalker in a duel while the remaining Slayers battled the Solos. The Supreme Overlord gained the upper hand, ensnaring Skywalker with his amphistaff. The Jedi also suffered a bite from the creature, injecting poison into his system. With Skywalker at his mercy, Shimrra drew Solo's lightsaber from his robes.

As Shimrra prepared to behead Skywalker, the Jedi used the Force to wrench the weapon from the Supreme Overlord's grasp. With the Yuuzhan Vong momentarily distracted, Skywalker swiftly shattered his Scepter of Power and then severed Shimrra's head, ending his life. Concurrently, Jacen and Jaina Solo pursued Onimi to the Citadel's private yorik-trema escape vessel, where the Shamed One revealed himself as the true Supreme Overlord, having manipulated Shimrra for decades using his powers. Jacen Solo killed him, and shortly thereafter, the Yuuzhan Vong fleet over Yuuzhan'tar—which had failed to destroy Zonama Sekot—learned of Shimrra's demise. For the first time in their history, the species was without a Supreme Overlord, their connection to the gods. Furthermore, because Shimrra had eliminated all potential successors, the Yuuzhan Vong had no one to assume his mantle and guide them. Utterly lost without their leader, the species surrendered. Soon after, the Sekot Accords were signed, stipulating that the Yuuzhan Vong would dismantle their weapons, renounce their warlike ways, and settle on Zonama Sekot—which the Jedi had discovered was a seed of the original Yuuzhan'tar. With this, the war concluded.

Shimrra existed under Onimi's control for approximately sixty years; Onimi used his Force abilities to manipulate Shimrra. During this time as Onimi's pawn, Shimrra was known for his cruelty, self-preservation, and manipulative nature. Although the Yuuzhan Vong were a violent species, Shimrra was considered exceptionally cruel.

Shimrra wanted to eliminate all infidels, seeing it as his divine duty. He was merciless, and by the end of the Yuuzhan Vong War, more than a third of the warrior caste had perished. Despite criticizing Tsavong Lah for wasting troops, Shimrra willingly sacrificed many Yuuzhan Vong to achieve his goals, mainly galactic conquest.

He loathed the Jeedai heresy, condemning its followers and leader, Yu'shaa, and killed all members of two Prefects' households simply for harboring heretics. Even after it was proven that Ngaaluh had planted the heretics, Shimrra refused to restore the reputations of the deceased intendants, stating their deaths would serve as a warning. Shimrra's hatred for the heresy was so intense that he had Zareb killed after Ngaaluh accused him of heresy, even though he knew the Priestess was fabricating evidence.

As Supreme Overlord, Shimrra was believed to be the Yuuzhan Vong's sole link to Yun-Yuuzhan, granting him near-absolute power over his people. He led all castes, commanding everything from the warrior caste's efforts to the priests' worship. Shimrra cherished his power and went to great lengths to protect it after overthrowing Quoreal. This included killing thousands of heretics and anyone who opposed him. Shimrra suppressed all knowledge of Zonama Sekot and killed Ekh'm Val for discovering it during the Yuuzhan Vong War to prevent others from learning about the world that supposedly foretold the Yuuzhan Vong's doom. He also concealed the emptiness of the eighth cortex for decades, knowing that its revelation would weaken his authority.

For much of his life, Shimrra had total control over the Yuuzhan Vong. He ruled harshly, often ignoring his advisors on the Great Council. Shimrra intimidated others into submission and was known for being ruthless and terrifying. Other Yuuzhan Vong feared him, and even Warmasters trembled in his presence. Additionally, Shimrra could sense others' thoughts due to Onimi's Force-sensitivity. High Prefect Yoog Skell warned Nom Anor never to even think of lying to Shimrra because of the Supreme Overlord's apparent omniscience. Shimrra was also skilled at manipulation and political intrigue. Onimi subtly influenced other Yuuzhan Vong using his Force powers, making it seem as though Shimrra had the mysterious ability to affect minds, enhancing his reputation as a terrifying, omniscient leader.

To reinforce his image as an omnipotent vessel of the gods, Shimrra had dovin basals—creatures that could create gravitational fields—installed in his Citadel's public and private thrones. These dovin basals made it seem as though those approaching his throne were walking uphill, making approaching the Supreme Overlord a monumental task.

Unlike most Yuuzhan Vong, Shimrra didn't trust the gods; he sought to overthrow them, much like he had overthrown Quoreal. Influenced by Onimi, Shimrra hated the gods and declared war on them. He believed the Yuuzhan Vong had surpassed them and were ready to take their place. Shimrra thought the gods feared this and conspired to destroy the Yuuzhan Vong. The appearance of Zonama Sekot in 29 ABY was just a test, he believed, and destroying it would prove the species' worth and force the gods to surrender.

By 29 ABY, Shimrra had become completely insane. Despite his ability to intimidate and manipulate, many Yuuzhan Vong had lost faith in him. His declarations that the gods were the true enemy, not the Galactic Alliance, were met with skepticism from the Elite, who were usually very fearful of him. Some had heard rumors of Zonama Sekot, and as the war worsened, their faith in Shimrra faltered, with some believing the Yuuzhan Vong were better off under Quoreal. Prefect Nom Anor and High Prefect Drathul were among those who had lost all confidence in Shimrra by the time of the Battle of Yuuzhan'tar. Anor believed Shimrra no longer provided stable guidance and that the species was lost.

To maintain the facade that Shimrra was the Supreme Overlord and Onimi was just his jester, Onimi had Shimrra abuse him publicly. This prevented anyone from realizing Onimi was the power behind the throne, and while many wondered why the Supreme Overlord kept a Shamed One as his familiar, they never questioned Shimrra directly. As Supreme Overlord, Shimrra was often addressed as "Dread Lord," "Great One," or "Fearsome One," among other similar titles.

Modified by Yuuzhan Vong shapers, Shimrra grew to a massive size. Luke Skywalker noted he was the largest Yuuzhan Vong he had ever seen, and Nom Anor observed that he towered over the Elite in meetings. The hau polyp creatures that formed his throne would sometimes burst under the strain of supporting his massive frame. Shimrra had thin limbs and a large head, with his torso and head covered in brands and tattoos honoring the gods. He wore gray robes made from the flesh of Steng, a rebellious Yuuzhan Vong Warmaster from millennia ago.

Shimrra had mqaaq'it-implanted eyes that constantly shifted colors, though they were usually red. His eyes glittered when he was angry, intimidating anyone under his gaze and making them feel as though their mind was being read. Nom Anor feared his eyes, finding the frequent color changes unnerving.

Shimrra Jamaane was created for The New Jedi Order, a nineteen-book series published by Del Rey between 1999 and 2003. The character was conceived during initial meetings between authors and Lucas Licensing editors, who planned the series' overall progression. James Luceno, then a consultant who later authored three novels in the series, suggested the idea that the Supreme Overlord could be a "puppet ruler."

Shimrra was first mentioned in Luceno's The New Jedi Order: Agents of Chaos I: Hero's Trial, published in 2000 as the fourth novel in the series. He was then mentioned in several other novels, serving as a major villain controlling events from the background and driving the invasion. He first appeared in Greg Keyes' The New Jedi Order: Edge of Victory II: Rebirth, published in 2001. Shimrra's true role as Onimi's puppet was hinted at in The New Jedi Order: Destiny's Way, and his importance grew near the series' end, with a major role in several books, culminating in the final novel, The New Jedi Order: The Unifying Force. Written by Luceno, this final installment revealed Shimrra's role as a figurehead for the apparent jester Onimi.

After The New Jedi Order concluded, Shimrra was mentioned in several novels and reference books. He was first identified as "Shimrra Jamaane" in Luceno's novel, Millennium Falcon, published in 2008. The New Jedi Order: Edge of Victory I: Conquest and Legacy (2006) 44 incorrectly spell his name as "Shimmra."