In the established timeline, specifically 29 ABY, a significant battle took place on the world of Mandalore. This conflict involved an invading force composed of Yuuzhan Vong combatants against the Mandalorian inhabitants who called Mandalore home. Early in the Yuuzhan Vong's campaign to conquer the galaxy, Boba Fett, the leader of the Mandalorians, formally allied his people with the extraterrestrial species. This alliance was contingent on the territory controlled by the Mandalorians being spared from the Yuuzhan Vong's expansion. However, Fett anticipated the Yuuzhan Vong would eventually betray the Mandalorians. Therefore, he secretly tasked his people with acting as clandestine saboteurs and intelligence gatherers, providing the information they obtained to the New Republic. The Yuuzhan Vong ultimately discovered Fett's treachery and launched an attack on Mandalore, bombarding the planet with singularity weapons and deploying thousands of soldiers.
The Mandalorians utilized their underground tunnel systems and formidable combat prowess to confront the Yuuzhan Vong. At the settlement of Bralsin, the Mandalorians engaged over a thousand Yuuzhan Vong warriors, killing them in large numbers. Although extensive wooded areas were destroyed, and nearly one and a half million Mandalorians perished by the battle's conclusion, the Mandalorians successfully expelled the Yuuzhan Vong from their planet. This made them the only group in the galaxy to independently defeat the invaders. The battle's aftermath left Mandalore with severe damage and a devastated infrastructure. However, the discovery of a deposit of beskar iron ore, uncovered by the Yuuzhan Vong's bombardment, led to an economic resurgence for the Mandalorians, enabling Mandalore to recover steadily from the devastation caused by the battle.
As the Yuuzhan Vong embarked from their original galaxy with the goal of seizing another galaxy, they dispatched a scout known as Nom Anor to lay the groundwork for a smoother invasion. Recognizing the potential of the Mandalorians as allies, Anor, using the alias "Udelen," made initial contact with Goran Beviin, a solitary bounty hunter, hiring the mercenary to carry out an assassination targeting a politician on Ter Abbes. Impressed by Beviin's competence in completing the task, Anor met with Boba Fett, the then-Mand'alor, the traditional leader of the Mandalorian clans, to secure ongoing Mandalorian mercenary support for his clandestine objectives. In 25 ABY, Anor's true identity was revealed when he assembled Fett and a small group of Mandalorian-operated fighters to witness the arrival of the Yuuzhan Vong fleet. Confronted with the reality of the extraterrestrial invasion by the Yuuzhan Vong, Fett negotiated the continued support of the Mandalorians in exchange for safeguarding the Mandalore sector.
However, despite the widespread belief that the Yuuzhan Vong and the Mandalorians were allies, Fett secretly instructed his people to gather intelligence on the aliens' bio-technology and disrupt their operations. Fett himself established a covert relationship with Kubariet, an agent from the New Republic Intelligence, after rescuing the Jedi from a Yuuzhan Vong officer during their assault on Birgis. The officer was killed, and Fett pledged to relay the intelligence gathered by his people to the New Republic through Kubariet, provided the Mandalorians' role as the source remained confidential. Despite these precautions, the Yuuzhan Vong eventually uncovered Fett's deception and sought retribution against the planet of Mandalore.
In 29 ABY, Yuuzhan Vong forces, originating from the already conquered world of Bandomeer, initiated an attack on Mandalore. Unlike their invasions of other planets, where the intent was to transform them to suit their needs, the Yuuzhan Vong's sole objective in attacking Mandalore was the annihilation of the Mandalorians. From space, the Yuuzhan Vong's ships indiscriminately deployed singularity weapons, creating massive craters across Mandalore's surface. Extensive forests were flattened, including those surrounding Mandalore's capital city, Keldabe. Entire communities built within the trunks and branches of ancient veshok trees were completely destroyed, and the structures that comprised Keldabe suffered significant damage during the assault. Once productive fields were contaminated and salted in an attempt to render them unusable.
The Mandalorians largely survived the space attack by utilizing a network of underground tunnels that extended from beneath many of their homes and structures into the distant mountains. When the Yuuzhan Vong deployed their soldiers to the surface, the Mandalorians retaliated, employing the tunnels and their exceptional martial skills to fight the Yuuzhan Vong. Over a thousand Yuuzhan Vong soldiers engaged the Mandalorians in Bralsin, a small suburb of Keldabe. Despite the area's limited defensive capabilities, the Mandalorians fought and defeated them in a massacre that would leave an enduring mark in the Force for over a decade afterward. Goran Beviin, the Mandalorian soldier who first encountered the Yuuzhan Vong, killed several of their warriors at Bralsin using his beskad sword. Large groups of Mandalorian supercommandos, native soldiers, and the Mandalorian Protectors, led by Boba Fett, fought to defend Mandalore from the Yuuzhan Vong, ultimately defeating and repelling the invaders. By the battle's end, nearly one and a half million Mandalorians had died, and although the Yuuzhan Vong's losses were even greater, Mandalore's population had been reduced by almost a third.
Despite the severe loss of life, the Mandalorians gained recognition throughout the galaxy as the only people to independently defeat the Yuuzhan Vong. Having openly turned against the Mandalorians, Boba Fett led the Mandalorian Protectors against the Yuuzhan Vong in defense of the galaxy, winning against the Yuuzhan Vong at Gyndine, freeing Tholatin from their control, and during the conflict at Caluula Station, the Mandalorian Protectors instilled fear of Mandalore's power in the Yuuzhan Vong.
Despite the Mandalorians' contribution to the fight against the Yuuzhan Vong, Mandalore received no reconstruction assistance from the Galactic Alliance after the war. The Galactic Alliance was the new galactic government formed during the war by restructuring the New Republic. More than ten years after the war's conclusion, Mandalore's population remained significantly reduced, many of its farms were left uncultivated, and areas of land were still barren and dark. At the site of the battle of Bralsin, the bodies of the dead Yuuzhan Vong were buried, but their remains often surfaced after heavy storms. Keldabe's damaged buildings were mostly repaired over time, but the hundred-meter-tall headquarters of the MandalMotors company still bore battle scars a decade after the Yuuzhan Vong's assault. This environment led to the rise of the kadikla movement, which advocated prioritizing Mandalore and focusing on its reconstruction. In 40 ABY, during a gathering of the clans at MandalMotors Hall in Keldabe, supporters of kadikla convinced Mand'alor Boba Fett to recall two million Mandalorians from across the galaxy to rebuild the damage and revitalize the poisoned farms. Responding to the Mand'alor's call, Mandalorians arrived in large numbers. Upon approaching the planet, two Mandalorians—a geologist and a minerals engineer—discovered that the Yuuzhan Vong's singularity ordnance had exposed a massive deposit of beskar iron ore north of the city of Enceri. The beskar deposit led to an era of economic recovery for Mandalore, with the Yuuzhan Vong's attack ironically strengthening the Mandalorian people.
The Yuuzhan Vong's attack on Mandalore was first introduced to Star Wars lore through a mention in the Star Wars Insider article The History of the Mandalorians, written by Abel G. Peña and published in March of 2005 as part of the Insider magazine's eightieth edition. The battle and its aftermath were later referenced in Karen Traviss' Star Wars: Legacy of the Force novels Sacrifice and Revelation, and alluded to in her digital book, Boba Fett: A Practical Man. Jason Fry and Daniel Wallace's reference book, The Essential Atlas, also notes the battle in its planetary entry for Mandalore, as does The Complete Star Wars Encyclopedia in its entry on Mandalore.