Rakghouls were a type of Sith-spawned mutants, engineered by the Sith Lord Karness Muur. Desiring an army to rule over and seeking a way to cheat death as so many other Sith before and after him did, Muur forged a talisman that he poured his spirit and power into, one that eventually came to be known as the Muur Talisman. Muur's talisman could turn almost any sentient being near him into a mindless rakghoul which he could control, but he found that there were exceptions: Force-sensitives and certain alien species could resist the talisman's effects. Thus, Muur engineered the "rakghoul plague," a virus-like disease that could be spread by a rakghoul's bite or a scratch from its claws, and that subjected the victim to a slower transformation into a rakghoul. Jealous and fearful of his power, Muur's Sith rivals killed him, and over time, the Muur Talisman came to reside on the Outer Rim world of Taris where the rakghoul plague ran rampant throughout the world's impoverished Undercity, creating vast numbers of rakghouls. The people of Taris would manage to put an end to the rakghoul presence on their world at some point prior to the year 19 BBY, and by the days of the Second Imperial Civil War, rakghouls were believed to be extinct.
However, with the Muur Talisman lay the ability to create new rakghouls, and the galaxy would see the return of rakghouls when the oubliette belonging to the Sith Lord Remulus Dreypa was uncovered by Darth Vader, and the Jedi Knight Celeste Morne who had entombed herself and the talisman within for safekeeping nearly four thousand years prior, was revived. Morne battled Vader, but was no match for the skills of the Sith Lord and his clone stormtroopers, so she called upon the talisman's power to turn the stormtroopers into rakghouls; outnumbered, Darth Vader fled, stranding Morne on the desolate moon she had awakened on with only rakghouls and the spirit of Karness Muur for company. Several years later, Morne and the talisman would escape the moon aboard a Rebel Alliance shuttle, turning the crew of an orbiting Imperial-class Star Destroyer into rakghouls during her escape. Later, after her ship had been taken aboard a Pellaeon-class Star Destroyer, Morne turned the crew of the Iron Sun into subservient rakghouls with the power of the Muur Talisman. Morne and her rakghoul crew later came into contact with former Jedi Cade Skywalker, who convinced Morne to join him in his campaign against the current Dark Lord of the Sith, Darth Krayt, after curing the rakghoul plague he had been infected with using his unique healing ability. During their attack on Krayt's forces, Krayt was killed and Morne convinced Skywalker to end her life and her suffering under Karness Muur's constant psychic presence. Skywalker then destroyed the Muur Talisman as it attempted to bind itself to a new host, effectively putting an end to the primary source of rakghouls.
In the wake of the Hundred-Year Darkness, waged between the Jedi Order and the Dark Jedi who sought to use the Force to alter and create life, and the Jedi's victory in the war's final battle on Corbos, the remaining Dark Jedi were taken into custody by Galactic Republic forces. These darksiders were stripped of their weapons and armor, and herded into unarmed transports that took them off-world and into the then unknown regions of the galaxy. These "Exiles", as they came to be known, landed on the primitive world of Korriban, home of the equally primitive Sith species; the former Jedi used their Force powers to amaze the Sith, who in turn elevated these outsiders to god-like status. Among this generation of the first "Lords of the Sith" was Karness Muur. Like many Sith, Muur desired a way to cheat the inevitability of death, and thus forged a Sith talisman that he poured his mind and spirit into, the Muur Talisman. But Muur's amulet had a second purpose: the talisman could use Muur's Sith magic to transform any nearby sentient into a mindless rakghoul, subservient to Muur's will and with which Muur intended to form an infinitely expanding army that would allow him to conquer the galaxy. There were exceptions, however, as both Force-sensitive beings and beings from a number of certain non-Human species proved immune to the talisman's effects. To combat this flaw, Muur engineered the "rakghoul plague," a virus-like disease that could be spread from a rakghoul's bite or a scratch from its claws. The infected victim would then slowly mutate into a rakghoul within a timeframe spanning mere hours.
Muur's jealous Sith rivals would lead to his body's physical death, though his spirit lived on with the talisman that over time, came to reside in the Undercity of the Outer Rim world of Taris, after its most recent owner had been crushed in a cave-in. Years passed as the rakghoul plague spread among the Undercity's Outcasts, transforming an untold number into mindless rakghouls that roamed the streets attacking any they came across.
By the start of the Mandalorian Wars, rakghouls had become an ever-present danger in Taris' Undercity. When Jedi Padawan Zayne Carrick fled into the Undercity seeking to escape his Jedi Masters—who had killed their others students earlier that evening after receiving a vision in the Force that one would become the next Sith, and blamed Carrick for their murders after he managed to escape—the Jedi Masters of the Taris Jedi Council were forced to fight through mobs of rakghouls and outlaw Gamorreans during their pursuit of the Padawan. After the Mandalorians conquered Taris, a Mandalorian scouting party and excavation team led by the Neo-Crusader scientist Pulsipher descended into Taris' Undercity where they located the Muur Talisman, claimed it for the Mandalorians, and took aboard Pulsipher's ship, the Mar'eyce. Unbeknown to Pulsipher or his warriors, Zayne Carrick, along with friend Marn "Gryph" Hierogryph and Jedi Covenant Shadow Celeste Morne, had stowed away aboard the Mar'eyce in an attempt to retake the talisman. When Pulsipher handled the talisman on board his ship, the Sith amulet attached itself to his arm, and afflicted Pulsipher's warriors with the rakghoul plague when they attempted to help their leader remove the talisman. Once the Mar'eyce landed at the Mandalorians' Ice Citadel on the frozen world of Jebble, these infected soldiers soon turned into rakghouls and began a series of events that led to more and more Mandalorians becoming infected upon being scratched and bitten.
To the surprise of Celeste Morne, these Mandalorian-spawned rakghouls—or "Mando-Raks" as one Neo-Crusader recruit deemed them—could use blaster weapons and were much more organized and apparently intelligent than previously witnessed. As the Mandalorians battled their rakghoul-turned comrades all across their Jebble base of operations, Zayne Carrick made contact with Mandalorian military commander Cassus Fett, bound for Jebble with Neo-Crusader transports. Carrick warned Fett of the rakghoul outbreak, and urged him not to land any ships for fear of the plague spreading further. Shortly after, Carrick was ambushed by a pair of rakghouls who dragged the Jedi to the laboratory of Pulsipher where the Mandalorian scientist, now realizing for himself the power the Muur Talisman possessed, demanded Carrick tell him how to unlock the relic's further powers over the rakghouls. In the presence of a Jedi, the talisman abandoned Pulsipher and the rakghouls he had previously commanded then slaughtered him. Before the talisman could bind itself to Carrick, however, Celeste Morne intervened and took the talisman onto herself. Using the Muur Talisman's power in conjunction with her own Force-sensitivity, Morne took control of the rakghoul horde. Over one million Mandalorian Neo-Crusaders had been turned into rakghouls, all now under the control of Morne. But with that power came the threat of dark side corruption from Karness Muur's spirit, and Morne chose to allow herself to be sealed away in the oubliette of the Sith Lord Remulus Dreypa, one of the Force-related items Pulsipher had collected in his Ice Citadel laboratory. With Morne sealed inside Dreypa's oubliette, the rakghouls lost their temporary intelligence and set upon each other, nearly killing Carrick and his companion, Gryph, as they fled the world aboard the Moomo Williwaw. Moments later, the Mandalorian fleet appeared over Jebble and, heading Carrick's earlier warning against the rakghouls, Cassus Fett ordered the orbital bombardment of Jebble via nuclear missiles. The rakghouls were wiped out, and the oubliette containing Morne and Karness Muur's talisman sunk beneath the water formed from Jebble's melted glaciers.
Though the Muur Talisman, the original source of the rakghouls, was lost beneath the surface of Jebble, the rakghouls were not gone from the galaxy. Taris' Undercity remained infested with the creatures, and more were transformed regularly after being bitten and scratched by pre-existing rakghouls. By the time of the Jedi Civil War, it was estimated that up to 60 million beings on Taris had been infected, but because the plague was mostly confined to the Undercity and lower levels generally populated by the planet's criminal class, the Taris government made little effort to combat the disease. The Mandalorians were later driven from Taris by Republic forces under the Jedi Knights Revan and Malak, but in 3956 BBY Sith forces under the recently turned Darth Malak occupied Taris. With them came a serum that could heal those infected by the rakghoul plague who had yet to complete the transformation, but the Sith restricted access to the serum to those Sith troopers that were sent down into the Undercity.
An amnesiac Revan—his memory of his time as a Sith Lord after falling to the dark side removed by the Jedi Council—later found a vial of the curative serum on the body of a dead Sith trooper while on Taris, and used it to heal several Outcasts infected with the rakghoul plague before finally giving it to the Upper City doctor, Zelka Forn. Forn was able to use this sample to synthesize a mass-produced serum that he shipped to the Outcasts and sold at a low price to all Tarisians. Shortly afterwards, Taris was subjected to a devastating orbital bombardment by Darth Malak's Sith armada, killing an untold number of beings on the planet, including a significant number of rakghouls.
During the Republic's efforts to rebuild Taris around the time of the first Great Galactic War, it was discovered that a number of rakghouls had survived the bombardment. Bands of these rakghouls roamed beyond the reaches of the Undercity and up to the surface, and reports claimed that some of the vicious creatures had evolved, displaying new powers.
The rakghouls would again reassert their infectious plague upon the galaxy with the help of a maddened scientist named, Sannus Lorrick. Spending years illegally experimenting on sentient species with gene-splicing and viral modification, the insane doctor would be stricken of his position as the to the Tion Hegemony and exiled. Seeking revenge, Lorrick would find the rakghoul plague as his new subject of obsession in his secret lab on Ord Mantell. There he would modify the plague to his will, creating rakghoul abominations such as Project Sav-Rak and sentients modified with the creatures' strength. Hiring a smuggler named Melarra to unknowingly transport one of his infected lab animals to the planet of Kaon, Sannus would finally get his revenge. The plague spread fast and wide, infecting 4 planets in the Hegemony and untold billions of people. Upon investigation, Republic and Imperial forces would find the cause of the plague, send strike teams to Lorrick's lab in the Lost Island and end the crisis.
Before Dr. Lorrick was defeated, the insane scientist would gift one his infected animals, a risp, to a smuggler named Zama Brak. The infected risp bit the smuggler, who was at the time traveling on the passenger liner called the Stardream, and start the plague on the cruise ship. Following the infection of the crew, the Stardream crashed on the planet Tatooine restarting a crisis of galactic proportion. The Sith Empire (Post–Great Hyperspace War) and the Galactic Republic would quarantine the planet and seek to contain the plague but would be met with disappointment when volunteers hoping to help in the efforts on the planet spread the virus further throughout the galaxy. Sometime during the plague, the CEO of Galactic Solutions Industries, Addalar Hyland's children were killed on the desert planet, which motivated the grieving father to create the Hyland Organization for Rakghoul Neutralization.
The disease would once again appear on the planet Alderaan where earlier reports indicated strange animal attacks, devoid of signs of Killik signatures, on patrolling soldiers. Addalar Hyland and THORN reacted quickly, using the retrofitted GSI weapon called the Spike, the organization was able to enter into the rakghoul tunnels to quell and study the deadly plague. Within the tunnels, THORN scientists discovered a new ecosystem that allowed the virus to flourish without the need to infect other creatures. Found in the rakghouls' DNA was a code that was similar to fungal species. This allowed the rakghouls to reproduce, first spawning as raklings and growing to more specialized subspecies such as the Eyeless and creatures that bred and harvested fungal matter.
Over time, the rakghouls were isolated on Taris and—possibly due in part to the serum Revan recovered—driven to extinction. But while the Muur Talisman remained, the threat of the rakghouls did as well. Approximately fourteen hundred years before the galaxy-spanning Clone Wars, ice miners discovered the oubliette of Dreypa beneath the surface of Jebble. A mystery to its finders, the oubliette became known as the "Jebble Box", and the inability to open it or scan what was inside bred numerous rumors as to its origins. Collectors bought and sold the box they believed to be an ancient Jedi treasure, and wars were even fought over the mysterious object. The Republic eventually fell to the machinations of the Sith Lord Darth Sidious, and was reorganized into the Galactic Empire, lorded over by the once Supreme Chancellor-turned-Galactic Emperor Palpatine, Sidious' public persona. By this time, the Jebble Box came into the possession of the crew of the Uhumele and they attempted to sell it to scholar and historian, Fane Peturri. Peturri was in league with Darth Vader, and Vader claimed the Jebble Box for himself during the proceedings, freeing the imprisoned Celeste Morne and with her, the spirit of Karness Muur. Upon learning Vader was a Sith, Morne attacked him, and the two engaged in a lightsaber duel on the desolate moon where she had awoken. Vader's skill was too great for Morne to fight alone and, faced with death and the possibility that once she was gone the talisman would attach itself to Vader, Morne was forced to tap into the talisman's power for herself, turning Vader's cadre of and Fane Peturri into rakghouls under her control. Outnumbered, Vader fled onto his shuttle. At the same time, the crew of the Uhumele were fleeing when Morne triggered the talisman's powers; Crys Taanzer, the only Human member of the Uhumeles crew, transformed into a rakghoul and Captain Schurk-Heren was forced to end her life. Morne was abandoned on the desert moon where she had been revived, left with only the spirit of Karness Muur and the group of rakghouls she had spawned as company.
Nearly twenty years later, Vader had not forgotten about Morne and in a mission to ascertain whether or not she still lived, he sent a company of heavily armed stormtroopers back to the deserted moon. Still very much alive, Morne used the Force to violently crash the Imperial shuttles on the moon's surface, and subsequently transformed their stormtrooper crew into rakghouls. With this knowledge, Vader turned to his spy, Wyl Tarson, with instructions to leak word of a secret Imperial weapon located on the moon, and ensure that it was noticed by members of the Alliance to Restore the Republic, a group of rebels that had been formed in the years since Vader had first confronted Morne as a force to oppose the oppressive Empire and restore the Republic that it had once been. Unable to resist an attempt to claim the Empire's weapon for themselves, several members of the "Rebel Alliance"—among them the likes of Princess Leia Organa, Luke Skywalker, Han Solo and his Wookiee companion Chewbacca, and the former clone trooper Able—undertook a mission of their own to the barren moon. Almost immediately upon touching down, the rebels were beset by the rakghoul horde, and several members were bitten and transformed into rakghouls themselves. A small number of the rebels escaped onto Han Solo's ship, the Millennium Falcon, while Skywalker was captured and taken to the cave where Morne had been living.
Convinced by the spirit of Karness Muur that the Jedi had abandoned her, Morne attacked Skywalker while Organa rushed to his aid. When Morne turned her lightsaber on Organa, the recently arrived Able opened fire in her defense, only to be turned into a rakghoul for his heroic efforts. Sensing the Force within both Skywalker and Organa, Muur dislodged his talisman from Morne and attempted to take a new, more maleable host. But Morne, coming to her senses, batted the talisman away from the two rebels and took the burden of the talisman back upon herself. As Morne turned her back on the two, Skywalker and Organa became the focus of Morne's legion of rakghouls, though the timely arrival of Solo and the Millennium Falcon allowed them to escape without injury. The rebels left behind the main shuttle they had used to reach the planet, and Morne decided to take it for herself; her numerous rakghouls followed her aboard and took their place as the new crew, lifting off and heading for orbit where an Imperial-class Star Destroyer awaited. Before the Imperial crew could attack the shuttle, Morne again tapped the powers of the Muur Talisman to transform those aboard into rakghouls and as she flew away into space, the Star Destroyer plummeted into the moon and exploded.
Once in possession of a ship, Morne found within herself a desire to explore the galaxy she had been away from for more than four thousand years. However, the desire was not her own, and in fact belonged to the spirit of Karness Muur; once Morne discovered this, she instead took her shuttle into the Deep Core with the intention of protecting the greater galaxy from the threat of Muur and the rakghouls. There she and her rakghouls would remain until 127 ABY, when her shuttle was taken aboard by the Pellaeon-class Star Destroyer, the Iron Sun. Morne believed that the Imperial ship that had captured her served the same Sith-led Empire that Darth Vader had served, and used the Muur Talisman's power to transform the entire crew of the Iron Sun into rakghouls. Over the next ten years, food on the Iron Sun ran out, and the rakghouls began to fight and cannibalize each other in order to survive.
In 137 ABY, the Iron Sun and its rakghoul crew captured another ship, the Mynock, owned by the former Jedi apprentice and Luke Skywalker's descendant, Cade Skywalker. Skywalker and his companions—Deliah Blue, Jariah Syn, along with Jedi Knights Shado Vao and Wolf Sazen, and the Imperial Knights Antares Draco, Ganner Krieg, and Azlyn Rae—began to explore the seemingly abandoned Star Destroyer, only to find the bones of dead rakghouls before being attacked by a group of still-living rakghouls. Morne was able to reassert control over the creatures and halt their attack, but not before Skywalker and Rae were infected with the rakghoul plague. Morne isolated the two from the others and informed them of their unfortunate status as victims of the rakghoul plague, promising quick deaths to Skywalker and Rae both once the transformation took hold. But Skywalker refused to accept his fate, and upon learning that the rakghoul plague was a disease created by but separate from the Force, he used his radical healing ability to cure himself and Rae, much to Morne's surprise.
Impressed by Skywalker's power, Morne vowed to aid him and his companions in their mission to kill the current Dark Lord of the Sith, Darth Krayt, and together they struck at the Imperial base on Had Abbadon. There, they engaged the Devaronian Sith Lord Darth Reave; Morne transformed Reave's stormtroopers into rakghouls that quickly turned upon their former master, and even Reave's dual lightsabers couldn't save him from being scratched before he managed to flee. Reave rushed back to the Temple of the Sith on Coruscant where he informed Darth Krayt and his Sith allies about Skywalker's presence on Had Abbadon before succumbing to the rakghoul plague, transforming into a rakghoul, and attacking Krayt. The rakghoul that had once been Reave was slain by Krayt's Hand, Darth Stryfe, and its body was looked over by the Sith scientist, Darth Maladi, who was surprised to see a rakghoul when they were believed to be extinct. A message from Celeste Morne, acting as Karness Muur and pretending to have Skywalker as her hostage, drew the Sith to Had Abbadon where they were ambushed: in addition to Skywalker, the Jedi, and the Imperial Knights, Krayt and his Sith were attacked by groups of Morne's rakghouls. The rakghouls would even defend Morne from the attack of Antares Draco, when he attempted to kill her and take the Muur Talisman for Emperor Roan Fel. The rakghouls were beaten back in large numbers by both Draco and the Sith, falling to Sith lightning and deadly lightsaber strikes, but Krayt himself was mortally wounded in a combined attack from Azlyn Rae and a Karness Muur-guided Morne. With Krayt down and the other Sith falling to the strike team, Morne turned to Skywalker with a plea to end her life before she fell completely under the sway of Muur's spirit. Skywalker acquiesced, and mercifully killed Morne with his lightsaber; with Morne dead, Muur's talisman attempted to bind itself to Skywalker, but Skywalker refused the temptation of the power Muur offered him, instead destroying the talisman with the Force, and seemingly driving the rakghouls back toward extinction.
Hideous and possessing an appetite for flesh, Rakghouls were non-sentient, and were most commonly simple and animalistic in their behavior, with some even referring to the creatures as "mindless". These feral rakghouls, known also as "lower rakghouls", were slaves to their instincts and especially their hunger, often traveling in packs numbering between four and eight, and attacking anything that looked or smelled like potential food. Though they were not a creature that held to any form of heirarchy, certain rakghouls, known to some as "rakghoul fiends", exhibited a manner of influence over their "lower" rakghoul brethren. Hardy and vicious, these rakghouls were generally believed to somehow maintain bits of their former intelligence, and would direct other rakghouls to trap and ambush prey; it was even rumored that these rakghouls could use weapons.
Rakghouls only truly reached their full potential, however, when under the power of the Muur Talisman. When a being possessed the Muur Talisman, they were able to enslave the rakghouls to their will, and command them as an army with the potential for nearly infinite expansion. Under the talisman's effects, rakghouls became more demure, and were able to call upon the knowledge and skills they had possessed in their former lives. Unfortunately, though, their former personalities could not be restored, as all that remained in the rakghouls was an imprint of who they had once been.
Rakghouls were a product of the Sith alchemy performed by the ancient Sith Lord, Karness Muur. When he forged the talisman in which he would later invest his mind and will, Muur imbued the amulet with the power to almost instantaneously transform nearby sentients into rakghouls that he could command and control. But the talisman's powers did not work on all: Force-users and certain non-Human species were immune to the talisman's effects. To rectify this, Muur engineered the "rakghoul plague", a virus-like disease which could be spread from a rakghoul's bite or scratch. Individuals infected with this disease would later transform into rakghouls themselves; incubation periods varied, though the infection's manifestation was generally a rapid and painful experience, becoming a rakghoul within a timeframe of six to forty-eight hours. The bodywide mutation manifested as the body would become twisted, skin pigmentation would drain and the victim would attain a whitened corpse-like state. Victims would also bleed from pores in the skin, and from places such as the eyes. In the years following the Mandalorian Wars, the Sith Empire born of Darths Revan and Malak possessed a curative serum that could save an individual infected with the plague, and the Jedi Cade Skywalker could cure an infected individual with his almost unique healing ability, but once a victim fully transformed into a rakghoul, the only means of salvation laid in death.