Yuuzhan'tar

At some point in their history, the extra-galactic Yuuzhan Vong were attacked by a species of droid known as the Abominor while they fought against against another droid species, the Silentium. The Yuuzhan Vong's living homeworld of Yuuzhan'tar aided them in their war against the invading droids by bestowing upon them the knowledge of creating living weapons. However, as the war dragged on, the Yuuzhan Vong as a species became increasingly violent and warlike. Eventually, they were able to defeat their enemies, and forced both droid powers to flee their galaxy.

Following the war, the Yuuzhan Vong went on a crusade to cleanse their galaxy of all forms of mechanical technology. They conquered much of their galaxy and either exterminated or enslaved conquered species. Among those species they conquered were the reptoid Chazrach, which became slave soldiers for the Yuuzhan Vong.

With much of the galaxy in their hands, the various Domains fractured and turned against each other, resulting in the devastating Cremlevian War. During the conflict, much of their galaxy was destroyed, including their homeworld of Yuuzhan'tar. However, the planet produced a seed which eventually became Zonama Sekot.

Separated from their original symbiosis with their homeworld, the Yuuzhan Vong were stripped from the Force, and as a result experienced great pain. Thus, the species saw pain as the only way to get back to that symbiosis and practiced body modifications on themselves. In place of their homeworld, the Yuuzhan Vong created several deities which would govern nearly every aspect of their civilization.

Towards the end of the war, Steng emerged as the first Warmaster. A rival Warmaster, Yo'gand, invented the Yo'gand's Core tactic, in which he used to destroy the planet Ygziir and its moon. The destruction of Ygziir resulted in the death of Steng and the end of the war. Eventually, Yo'gand united the Domains into a single socio-political entity and became the first Supreme Overlord of the Yuuzhan Vong.

However, with much of their galaxy ruined, the Yuuzhan Vong began a long trek to another galaxy in search of a new home. For millennia, the species was forced to travel through the Intergalactic Void in massive worldships. During this period, the Yuuzhan Vong nearly destroyed themselves. Violence and competition had been built into their society, and without an external target, they focused their aggression against each other. Though there were no all-out wars in the magnitude of the Cremlevian War, the Domains continued to fight each other for the favor of the Supreme Overlords.

In Daniel Wallace's endnotes for The New Essential Guide to Droids, the war between the Silentium and the Abominor is strongly implied to be the root cause of the technophobia of the Yuuzhan Vong.

• Coruscant and the Core Worlds
• The New Essential Chronology
• The New Essential Guide to Alien Species
• The Complete Star Wars Encyclopedia
• Legacy Era Campaign Guide