The Clash at Columus unfolded amidst the First Great Schism, a war that took place in 24,500 BBY. It pitted the Jedi Order against the dark side-aligned Legions of Lettow. On the planet of Columus, Jedi Master Awdrysta Pina's armies met the commanded forces of the Legions, led by General Xendor. Pina's warriors employed a Force-enhanced battle-meld, giving them a tactical edge over the Legions of Lettow, and ultimately, Pina slew Xendor himself.
Simultaneously, during the conflict, a contingent of Dark Jedi Legionnaires sought to ensnare a group of Jedi, including the Padawan Danzigorro Potts. In the intense fight that followed, Potts extinguished the lives of his former comrade, the Legionnaire Blendri, and her apprentice, Cuthallox. Suffering fatal wounds himself, Potts, before his demise, recorded an account of the battle on a datacard. This recording became widely known as the Columus Data Card and, tens of millennia later, served as inspiration for several operas.
Back in 24,500 BBY, the Jedi Order was embroiled in what would later be called the First Great Schism, a war against the Legions of Lettow, a dark side of the Force faction under the leadership of General Xendor, once a Jedi Knight. Xendor and his followers, aiming to prevent the Galactic Republic worlds from becoming embroiled in what was essentially an internal Jedi dispute, attempted to swiftly conclude the war by taking the fight to the Order's headquarters on the distant planet Ossus.
However, the Legions of Lettow suffered a setback, and the conflict soon spread to the Republic's Core Worlds. There, on Corulag, the Jedi Padawan Danzigorro Potts hunted down and killed his former Master, Jook-jook H'broozin, who had joined the Legions of Lettow. Nevertheless, Potts' similarly-renegade best friend, the former Jedi Knight Blendri, and her apprentice, Cuthallox, continued to evade the Padawan, fleeing from one world to another until they finally arrived on Columus.
On Columus, the armies commanded by the Jedi Master Awdrysta Pina, also known as the Green Blade, clashed with the legions led by Xendor, with the combatants brandishing Force-imbued blades. The Jedi forces employed a battle-meld, a technique created through the Force that allowed them to fight as a unified whole, with all fighters moving and reacting in perfect synchronization. According to Steel Hand of Palawa Arden Lyn, Xendor's lover, such a surrender of individuality, which made the Jedi forces resemble hive-minded insects, was anathema to the Legions of Lettow, and this gave the Jedi a decisive advantage in the battle.
Pina's forces pressed their attack, isolating Xendor and his vanguard from the rest of his forces. One by one, the Jedi vanquished the mightiest warriors of the Legions, including Sethul Asaiage and Tun Bohoi, until finally Pina himself, reportedly wielding his emerald-colored swords, struck Xendor down. Lyn, who was not a combatant in the battle, later claimed to have witnessed her lover's death as if she had been present. She also claimed that, "rather than be drunk by the Green Blade and destroyed," Xendor's "spirit fled into the Dark."
In another part of the battle on Columus, a group of nearly thirty Dark Jedi from the Legions of Lettow attempted to trap a similarly-sized group of Jedi Knights in a ravine. In the resulting intense and rapid confrontation, Danzigorro Potts extinguished the lives of Blendri and Cuthallox, although, despite being the last survivor of the engagement, the Padawan himself also suffered fatal injuries. Potts then received a transmission informing him of Xendor's demise.
As he lay dying on the battlefield, Potts made an audio recording on a data card. In the recording, which was intended for any Jedi who might discover it, the Padawan briefly recounted the battle—mistakenly claiming to be the sole survivor of the engagement—and expressed his relief at the impending end of the Great Schism. He then shared a sympathetic view of his former best friend, Blendri, before pondering whether the Jedi needed a common external enemy to prevent the Order from descending into another internal conflict. Subsequently, Potts succumbed to his injuries.
Following the Battle of Columus, Pina's armies advanced on the planet Lettow, the location of the Legionnaire Academy, with the goal of eliminating the remaining Legions of Lettow. Although Arden Lyn had inherited leadership of Xendor's forces, she recognized that the only viable strategy was for the Legions to hold off the Jedi forces at Lettow long enough for them to escape beyond the Republic's borders. Pina eventually tracked down the fleeing Lyn to Irkalla, and during the ensuing confrontation, she was placed in a state of stasis that lasted until 4 BBY.
The exiled fallen Jedi Sorzus Syn mentioned the Battle of Columus in her chronicle, authored after the conflict known as the Hundred-Year Darkness in 6900 BBY, arguing that Xendor's demise during the confrontation was not a "tragedy" compared to the Jedi's failure to change their supposedly dogmatic ways after the end of the First Great Schism. In 4 BBY, Lyn was awakened from her stasis by agents of the Galactic Empire and recounted the Battle of Columus in a debriefing, selections of which were filed by Grand Inquisitor Laddinare Torbin.
By the time the New Republic had replaced the Empire as the dominant galactic power, the final words of Potts' recording on the now-popular Columus Data Card inspired three operas performed on Coruscant, the capital planet of the galaxy. The 40 ABY publication Jedi vs. Sith: The Essential Guide to the Force by the Jedi historian Tionne Solusar also included a mention of the Battle of Columus in connection to the Columus Data Card.
The reference book The New Essential Chronology from 2005 by Daniel Wallace and Kevin J. Anderson was the initial source to mention Xendor's death at the hands of the Jedi. Ryder Windham's 2007 book Jedi vs. Sith: The Essential Guide to the Force later introduced the battle known as the "conflict on Columus," and the 2009 reference book The Essential Atlas by Wallace and Jason Fry firmly established Xendor's death during that confrontation, explicitly referred to as the "battle on Columus." Book of Sith: Secrets from the Dark Side, a 2012 book by Wallace, provided an illustration of the event and introduced its proper name, the "Battle of Columus," although an image caption in the book initially misidentified it as the Battle of Corbos.