A lightsaber battle unfolded in 990 BBY. Darth Bane, the remaining Dark Lord of the Sith, and his apprentice Darth Zannah, clashed with five Jedi led by Lord Valenthyne Farfalla. Zannah, having escaped the Jedi Temple on Coruscant, journeyed to the Deep Core planet of Tython to alert Darth Bane that the Jedi knew of their existence and were in pursuit. The Sith fortified themselves within the dilapidated fortress of the deceased Dark Lord Belia Darzu, anticipating an impending fight with their adversaries. Determined to eliminate the last Sith, the Jedi stormed Darzu's fortress and engaged Darth Bane and Zannah. Despite their numerical advantage, all five Jedi were killed by the two Sith, who proved superior in both lightsaber combat and command of the Force.
A decade following the destruction of the Sith Brotherhood of Darkness, Darovit, a young man sensitive to the Force, traveled to Coruscant to present evidence to the Jedi Council proving that Darth Bane, the Dark Lord of the Sith, had survived the final battle of the war. However, he was thwarted when he unexpectedly sensed his cousin Zannah within the Jedi Temple Archives, just as the Sith apprentice's concealed false light-side aura faltered. Upon seeing her, Darovit had a sudden change of heart, and he cautioned Zannah about the Jedi's intentions to pursue her and her Master. Despite her initial anger, Zannah quickly regained her false aura and completed her research into the nature of orbalisk parasites for Darth Bane, who had been afflicted with them ten years earlier. Zannah also discovered Darovit's healing abilities and decided to exploit them to rid Bane of his orbalisk infestation. After obtaining an ancient hyperspace route to Tython from an Archive computer, Zannah swiftly departed the Temple with Darovit, leaving Coruscant aboard her personal starship, the Loranda.
Meanwhile, within the Jedi Temple, Jedi Johun Othone sought out his former Master, Valenthyne Farfalla. Othone believed he possessed sufficient proof of the Sith's existence, based on Darovit's testimony, and had brought Darovit to Coruscant for a meeting with the Jedi Council. Othone finally located Master Farfalla and explained the situation. They then proceeded to the Archives where Othone had left Darovit, only to discover that the young man was gone. After a quick investigation, the two Jedi learned that Darovit had fled to Tython with Zannah. Armed with this information, Farfalla assembled a team of four Jedi: Raskta Lsu, Johun Othone, Sarro Xaj, and the Ithorian Master Worror. With Farfalla as the fifth, they departed aboard Master Lsu's personal attack vessel, Justice Crusader. The Jedi arrived on Tython, landing their ship near the Loranda and Bane's ship, the Mystic, and entered the temple of the ancient Dark Lord of the Sith Belia Darzu. There, the Jedi Masters and Knights immediately engaged Bane and Zannah in combat.
The duel took place in a circular room with a door on each side. Farfalla and Lsu, empowered by Jedi Battle meditation, entered from one door, while Othone and Xaj entered through the other. Their strategy was a two-pronged attack, simultaneously cutting off any potential escape for the Sith Lords. Worror entered last, focusing on his Battle meditation rather than direct combat. Upon seeing the Jedi, Bane charged towards the Masters, lightsaber ignited. His initial attack was met head-on by Raskta Lsu, an Echani Jedi Weapon Master. She attacked Darth Bane, but his orbalisk armor prevented her from inflicting any significant damage. As Bane charged towards her, Lsu evaded him, but Bane's attention shifted to Farfalla, who also dodged the Dark Lord's advance. Lsu again leaped towards Bane, only to be met with a powerful Force push that sent her flying across the room. Farfalla's quick thinking created a Force barrier to cushion her impact. She recovered, but Bane's focus was now on Farfalla.
Bane unleashed a barrage of purple Sith lightning at the Equine Jedi, but Farfalla again used a Force barrier for protection. The lightning pierced the barrier but was intercepted and deflected by Raskta Lsu. Bane charged again, and the Masters engaged him. During the duel, Bane elbowed Lsu in the ribs with enough force to lift her off her feet. The Echani woman was momentarily incapacitated, and Darth Bane finally engaged Farfalla. Lsu shouted to Farfalla to be wary of Bane's unique lightsaber, which was giving him an unusual advantage, but Bane's sheer physical strength knocked Farfalla's lightsaber from his hand. Lsu saved him again, tripping Bane with a scissor-kick from behind. As he recovered, Lsu directed her attacks at his face—the only exposed area of his body. Bane was losing ground as Farfalla tried to rejoin the duel, but Lsu saw him as a hindrance and told him to hold back. Farfalla instead assisted his colleague by protecting her with another Force barrier. Meanwhile, Bane was being continuously pushed back by Lsu. Suddenly, he disengaged and raced towards the source of the Jedi's strength: Master Worror. Bane realized that Worror's Battle meditation was empowering the Jedi, and with Worror unprotected, Bane rushed him as fast as he could.
On the other side of the room, Darth Zannah held her own against Sarro Xaj and Johun Othone. Xaj, a physically imposing Human male wielding a double-bladed lightsaber (much larger than Zannah's), attacked her with brute strength, causing her to lose her balance. However, Othone's Niman style disrupted Xaj's assault, helping Zannah regain her composure. Zannah was familiar with a purely offensive style of Djem So, having only learned to defend against her Master, who had little need for defense due to his symbiosis. She was unprepared for an opponent who incorporated defensive maneuvers, and Sarro Xaj's refined technique caught her off guard.
On several occasions, Xaj's strength overwhelmed Zannah's defenses, though not to the point of incapacitation. His ferocity was balanced by the awkward rhythm of Othone's dueling. Because of Othone's unpolished style, Xaj had to minimize his own assault to avoid striking his partner. This disruption allowed Zannah to regain her rhythm and erect her impenetrable defense once more. An opportunity arose to cut Othone down, but Zannah declined, realizing that he was more of a hindrance to his colleagues than her. She nimbly danced around her assailants, giving ground and regaining strength as they advanced. Suddenly, Farfalla beckoned the Knights; realizing Bane's near invulnerability, the Equine Jedi called for help, which Othone willingly provided.
He reacted immediately by leaping over to the Masters and joining the battle simultaneously with Farfalla. With three Jedi now attacking him, Darth Bane was forced into a defensive position. With Othone on his right and Farfalla on his left, Raskta Lsu attacked the Dark Lord from the middle, all the while capitalizing on Othone's clumsiness and Farfalla's grace. Lsu's skill allowed her to benefit from the hindrance Othone had previously been to Sarro Xaj. But despite the strength of their attack, the Jedi could neither subdue nor defeat Bane. Othone caught a glimpse of Bane's wrist between the shells of the orbalisk armor and aimed his next strike there. The blow startled Bane, cutting him deeply and forcing him to drop his weapon. The pain, however, fueled Bane's rage, and he unleashed a Force wave that knocked his oppressors away. Now with a clear path, Bane moved to strike down the Ithorian Jedi. He recalled his lightsaber and approached Worror. When Othone realized Bane's intentions, he used the Force to push Worror out of harm's way. This marked the beginning of the end for the Jedi.
Johun Othone's Force push saved Worror, but at the cost of his beneficial battle meditation. Sarro Xaj immediately felt the effects, no longer as strong as before. As he turned his head to see what had happened, Zannah seized the opportunity to cast her spell of insanity on him. Xaj was instantly driven mad, and Zannah swiftly cut him down. She then concealed her Force presence with her sorcery, snuck up behind Raskta Lsu, and impaled her. Lsu collapsed to the floor, dead. With only two Jedi remaining, Darth Bane easily severed Othone's weapon-hand and proceeded to disarm and behead Farfalla. Bane then attacked Worror, slashing at his four throats and fatally wounding him. However, before Bane could use his purple lightning to electrocute the wounded Othone, Worror used his last strength to trap himself and Bane in a Protection bubble, causing the Force lightning to electrocute both of them. Worror died, and Bane fell to the floor unconscious, a smoking, orbalisk-encrusted husk.
Othone gave his opponent a pleading look, but it was ignored. Zannah ran her lightsaber through his chest as he lay on the floor. With Johun Othone dead, the battle was finally over. Zannah rushed to Bane's side and began to aid her wounded Master. Noticing the silence outside, Darovit emerged from the closet where Zannah had told him to hide. Seeing Bane, he informed Zannah that dead orbalisks immediately release toxins, and that Bane's chances of surviving their poison were slim. Zannah knew of only one other individual with enough healing capacity to help her, and he was back on Ambria. Shortly after, the Sith left Tython in search of the healer Caleb on Ambria.
Drew Karpyshyn created the duel on Tython for his 2007 novel Darth Bane: Rule of Two.