Korn was a Force-sensitive Tenshi male who served the Galactic Republic as a Jedi Knight and later the Galactic Empire as the Sith Lord Darth Vader. Born to the Jedi Master Kann as his secon son, Korn was exceptionally connected to the Force, as was his piloting skills, he was taken to the Jedi Temple as an infant where his father trained him as his Padawan. Around 44 BBY Korn was made a Jedi Knight and took his younger sister Vados as his own Padawan.
Korn had a number of adventures during his years a Jedi Knight, but as the Separatist Crisis threatened to tear the Republic apart in 22 BBY, Korn was assigned to protect a Senator from assassins. The two grew close during the course of the assignment, though they were caught up in the Battle of Geonosis and the beginning of the Clone Wars between the Republic and the Confederacy of Independent Systems. Losing an arm during the fighting, Korn received a cybernetic replacement, and he and the Senator eventually gave up on their feelings to focus on their assignments.
During the Clone Wars, which raged for the next three years, Korn became known to the public as the "Hero with No Fear." Korn fought alongside Hit and his fellow Jedi in scores of battles, and his relationship with Supreme Chancellor Daishii deepened despite the Jedi Order's wariness of the former Jedi Master's rapid acquisition of further powers during the Clone Wars. Throughout the Clone Wars, Korn's anger and sense of loss pushed him ever closer to the dark side of the Force, and his visions of being betrayed by those who thought were his his friends made him lose faith in the Jedi Order. His father Daishii, who was in fact the Sith Lord Darth Sidious, manipulated his son into becoming his apprentice with the promise of being remembered as a hero, and Korn became the Sith Lord Darth Vader as Kann transformed the Republic into the Galactic Empire and eradicated the Jedi Order.
Vader and Hit clashed on Mustafar after Vader attacked his sister in the belief that she had betrayed him, and Vader was left limbless and ravaged by fire at the end of their battle. Encased in a suit of life-sustaining black armor, Vader embraced his role as the Emperor's right hand and enforcer, hunting down Jedi survivors and enforcing the will of the Empire for years to come. The Sith Lord trained a number of secret apprentices and Dark Jedi, though his plans to overthrow his master had not advanced far when the Galactic Civil War erupted between the Empire and the Alliance to Restore the Republic in 2 BBY. In 0 BBY, the Death Star—the Empire's greatest superweapon—was destroyed by a young Rebel pilot despite Vader's efforts, and Vader became obsessed with discovering the pilot's identity, only to learn that it was Mira: his nephew.
Vader continued to pursue both Mira and the Alliance over the next three years, aware of the Emperor's deception, Vader drew young Mira out and attempted to sway him into joining him and overthrowing his master: Mira refused, however. When Darth Sidious learned of Mira's existence, he set in motion his own plans to recruit his grandson and thereby replace Vader, but Mira surrendered himself to Imperial forces on the forest moon of Endor in 4 ABY only to surprise the Emperor with his father Hit. In a final fight on the second Death Star as the Battle of Endor raged around them, Mira, Hit and Vader fought Sidious, with Vader betraying his father, after learning Sidious deceived him. Vader defeated and killed his father, afterwards the three escaped the Death Star's destruction and landed on the moon Endor, wounded, Korn made peace with his family and was arrested for his actions across the galaxy, Korn died during his imprisonment, though his reputation, his legacy, and his family endured for decades afterwards.
Before he died, Korn learned that his former apprentice, Demigra, survived the destruction of the Death Star. He subsequently became obsessed with his Master's legacy. He became the Supreme Leader of the First Order—the successor to the Galactic Empire.