He is born as Dessel on the planet Apatros, the son of a miner named Hurst. Hurst, an abusive alcoholic, blames the boy for the death of his wife in childbirth, and often calls him his "Bane". His father takes him into the mines at a young age, and the boy is bullied and abused well into adulthood. He is powerful in the dark side of the Force, and unconsciously uses this power to kill his hated father. The authorities did an autopsy, and said Hurst had died of natural causes. Years later Dessel will learn he killed his father with the Force.

After he kills a Republic Navy ensign in self-defense, Dessel flees Apatros and joins the armies of the Brotherhood of Darkness, a band of Sith Lords. His instinctive use of the Force (which he initially believes to be a myth) brings him to the attention of the Sith Lord Kopecz. Dessel is sent to the Brotherhood's Academy on Korriban to be trained in the ways of the dark side. Dessel (who renames himself Bane) becomes a star pupil after killing another student in cold blood. In particular, he attracts the attention of Sirak, the top student at the Korriban Academy.

After Bane realizes that he had indeed killed his father with the dark side, he subconsciously retreats from the Force, losing his power. Bane falls out of favor in the Academy, and is eventually refused any personalized training. Months later, in a vain attempt to reestablish himself, Bane challenges Sirak to a fight and is seriously injured in the ensuing duel.

Bane's training in and ascension to the Sith is detailed in both Path of Destruction and Jedi vs. Sith. As a student, he meets a new apprentice (and former Jedi) named Githany, who secretly plans to use him to bring down Sirak. Githany reestablishes his connection to the dark side by showing him in secret what the Sith Lords are teaching her. Most importantly, Bane studies tomes from the Golden Age of the Sith, and realizes that the new teachings of the Brotherhood of Darkness are incomplete.

Githany tells Bane that she intends to challenge Sirak, assuming that Bane would offer to assassinate him to spare her. However, Bane surprises her by revealing his intentions to destroy Sirak personally in the dueling ring, and that he had known all along she was using him. During the duel, he seriously wounds his opponent, but stops just short of killing him.

Bane leaves the academy, hoping to find the secrets of ancient Sith Masters in the Valley of the Dark Lords on Korriban. To his disappointment, however, he finds nothing. He returns to the academy to fill himself up from his starvation; there, Githany lures him to the archives, apparently intending to kill him. When the trap comes to fruition, however, Bane realizes that the trap is actually meant for Sirak. Githany kills Sirak's henchmen, and Bane defeats and kills his old nemesis in a lightsaber duel.

Bane takes the long-abandoned Sith title of Darth, leaves the Brotherhood, and travels to Rakata Prime. There, he discovers a Sith Holocron left behind by Darth Revan. Bane completes his training, learning numerous Sith techniques, including the "thought bomb" designed to kill all Force-sensitive beings in reach.

Bane then devises the "Rule of Two": Only two Sith Lords, a master and an apprentice, are allowed to exist at one time ("One to embody power and one to crave it.")

At this time, Kaan orders that all of the students on Korriban be made into Lords and brought to battle on Ruusan. Kaan sends Swordmaster Kas'im to bring him back to Ruusan to join the Brotherhood on pain of death. Upon meeting his former teacher, Bane considers taking him as an apprentice, but ultimately kills him after being refused.

Bane sends a staged message to Kaan asking to join the Brotherhood; Githany volunteers to kill Bane. Unknown to Githany, Bane had also sent the thought bomb, supposedly as a token of goodwill to the Brotherhood. Githany finds Bane, and pretends to accept his offer to join the Brotherhood. He is then rendered violently ill by poison Githany slipped him in a kiss. Barely alive, Bane eventually finds a healer named Caleb, and extorts his help by threatening his daughter. Caleb cures Bane of the poison and brings him back to health.

Bane returns to Ruusan, where Kaan agrees to follow his lead in battle. During meditation, Bane uses his own body and power as a focusing agent to unleash a wave of destruction upon the forests of Ruusan, where the Jedi's Army of light is hiding.

When the other Sith Lords mutiny, Bane goes to camp and orders the commander of the space forces to engage the Jedi fleet. Realizing he is facing defeat, Kaan retreats to underground caves with the other Sith Lords. When the thought bomb detonates, it destroys the Jedi and Sith armies. The thought bomb was eventually destroyed by Kyle Katarn, thousands of years later.

In both Jedi vs. Sith and the end of Path of Destruction, Bane meets a Force-sensitive young girl named Rain, who had been brought to Ruusan by the Jedi. When Rain's friend is accidentally killed by two Jedi troops, her anger draws on the dark side, snapping both of the soldiers' necks. When Bane happens upon this scene, he realizes he has found a worthy apprentice.