The Leveler, also known as the Great Leveler, was a formidable Nameless creature. It possessed the capacity to overpower individuals sensitive to the Force and to sever their connection with it. This being moved on four legs and had claws. The creature was confined within ice inside the Shrine, which was located within the caves of the planet Rystan. It was guarded by droid attendants and venerated by the ancestors of Eye of the Nihil Marchion Ro, who were unaware that the name they used was not its true designation. The Ro family held the being in reverence, viewing it not as a god but rather as an instrument of equilibrium.
Radicaz Dobbs, a smuggler and prospector, obtained the egg from which the Great Leveler would eventually hatch. He retrieved it from the Nameless homeworld situated in Wild Space around 382 BBY. Dobbs, who occasionally traded in Force artifacts, mistakenly believed the egg to be a large jewel. He was later approached by Elecia Zeveron, who led the Path of the Open Hand, a cult situated on the planet Dalna. This group believed that the Force should be "liberated" from those who used it. When Zeveron showed little interest in his other items, Dobbs revealed the egg, which immediately piqued her interest. Under the influence of a mind trick by the Mother, Dobbs agreed to help the Path acquire more Force artifacts, while Zeveron took possession of the egg. Kor Plouth, a Force-sensitive member of the cult, felt disturbed by the egg and shared her feelings with her girlfriend, Yana Ro.
Zeveron eventually hatched the egg when two Jedi, Zallah Macri and her Padawan Kevmo Zink, burglarized the Path compound while searching for the Rod of Seasons, an artifact that the cult had stolen from Hynestia Prime. Upon hatching, the Leveler swiftly overwhelmed and petrified Macri. Zeveron remained unharmed but experienced temporary petrification effects and developed grey streaks in her hair. Zink fled, but the creature's energies eventually overwhelmed him, and he was petrified to death in the arms of Marda, Yana's cousin, with whom he shared a mutual attraction.
The cult members hailed the Leveler as a gift from the Force. Yana discovered that the creature was drawn to the Rod of Seasons, but the Path's Elders named her the Champion, believing that the Leveler was attracted to her, an Evereni woman, rather than the artifact. Harboring a grudge against Zeveron for Plouth's death, Yana hoped to use her new position within the sect against the leader.
More than a month later, the Mother transported Yana and the Leveler to Jedha with the intention of liberating the Holy City from Force "abusers," including the Jedi, the Lonto, and the Matukai. As The Herald addressed the Convocation of the Force, Yana accompanied him and eventually unleashed the Leveler, using the Rod of Seasons while the Herald incited a riot among the crowd outside the building. The Leveler's presence drove Force users in the crowd to the brink of insanity, causing them to unleash their powers against the citizens and triggering a riot. Amidst the chaos of the ensuing Battle of Jedha, the Children of the Open Hand stole the Rod of Daybreak, which was combined with the Rod of Seasons to create the Rod of Power, granting total control over the Leveler. Leebon, a respected Jedi Master, was among those slain by the Leveler during the battle.
Having secretly allied with the Herald to overthrow the Mother, Yana managed to retrieve the Rod of Daybreak and return it to Dalna, where the Mother reforged the Rod of Power, gaining complete control over the terrified Leveler. Meanwhile, Marda, now radicalized, participated in a mission to Planet X, where the Path acquired more Nameless eggs. Marda then seized absolute control of the Path, renaming it the Path of the Closed Fist, abandoning Yana and leaving the Herald and the Mother to follow her. The newly acquired Nameless were deployed in the Battle of Dalna. The Leveler became the leader of the Nameless pack, which preyed on Path Force-sensitives—regardless of whether they used their powers or were even aware of their Force sensitivity—as well as Jedi. Ultimately, the Battle of Dalna, remembered as the Night of Sorrow, resulted in defeat for the Path.
Horrified by the Nameless's actions, particularly their indiscriminate targeting of Path members, Marda used the Rod of Power to gather the Leveler and its pack in a single cavern. This allowed Yana to detonate explosives, causing a flood that wiped out the assembled creatures. The Leveler alone survived the Ro cousins' actions, reaching the edge of the Path camp where Marda found it. Retaining the Rod of Seasons, which had broken off from the Rod of Daybreak during the flood, she once again bound the Leveler to her will and resolved to initiate a new plan to liberate the Force, beginning by killing the Mother—whom she had discovered was a Force user manipulating the Path for her own purposes—and fleeing with the creature aboard the Gaze Electric. Forming the original Nihil pirates, she cared for the Leveler. It eventually became known as the "Great Leveler" but was, at some point, frozen in ice on the planet Rystan.
Following the Battle of Dalna, Yoda and Creighton Sun, both Jedi Masters, decided to conceal the existence of the Nameless, fearing their potential use against the Jedi. While they intended to investigate further, their actions left the Jedi unprepared for the continued threat posed by these creatures. Over a century after the Night of Sorrow, Marchion Ro, Marda's descendant, visited Rystan with Udi Dis, a Force-sensitive Talortai, and was led to the Shrine by his cousin, Kufa. By then, the Leveler had been unattended for some time. As they neared the Shrine, Dis began to be overwhelmed by the Leveler's presence. Ro, who had brought Dis to assess the Leveler's power, killed both the Talortai and Kufa, retrieving the Leveler and confining it aboard his flagship, the Gaze Electric, at the Nihil marauder base on Grizal. Ro had previously acquired both halves of the rod necessary to control it.
Aboard the Gaze Electric, Kisma Uttersond, a Chadra-Fan doctor, constructed a heating apparatus for the ice block and implanted a camera into the Leveler's back, allowing Ro to monitor its movements. Later, during a Jedi assault on the Nihil's camp, Ro used the two halves of an artifact to control the Leveler, releasing the creature, which leapt from the starship, driven by an insatiable hunger resulting from its time in the ice. Although Ro soon used the artifact to recall the Leveler to the Gaze Electric, which escaped into hyperspace, the Padawan Bell Zettifar was overwhelmed, and Loden Greatstorm, a Jedi Master, was turned to stone.
Seeking to determine if the Leveler's effects on Grizal could be replicated, Lourna Dee, a Nihil Tempest Runner, transported the Leveler to the planet Xais, where the Nihil had taken over a former gas refinery. On Xais, Keeve Trennis and Terec, both Jedi Knights, had attempted to infiltrate the Nihil's ranks but had been discovered. Dee had Uttersond present a box containing the Leveler, opening it in the presence of the Jedi and exposing them to its power. Trennis was overwhelmed by the Leveler, while Terec began to slowly turn to stone—as did Ceret, their bond-twin, elsewhere aboard the Jedi cruiser Ataraxia. Ceret guided the Ataraxia to Xais, where the Jedi clashed with the Nihil forces, prompting Dee to have Uttersond load the Leveler onto her ship as she attempted to flee.
Having proven the power of the Nameless through the Leveler's deployments, Ro sought out and gathered more of these beings from a hidden planet. In possession of a large group of Nameless, Ro unleashed them upon the Starlight Beacon as the Nihil destroyed it. Upon being affected by one of the creatures as she entered the falling space station, Trennis believed that the Great Leveler itself was part of the attacking force.
The Leveler exhibited a blue hue. Its physical characteristics included four legs, hoofed feet, disproportionately large black eyes, and tendrils surrounding its nose.
The Great Leveler made its debut in the 2021 novel The High Republic: The Rising Storm, authored by Cavan Scott as a component of the Star Wars: The High Republic publishing initiative.