This skirmish began as a rescue operation but devolved into utter pandemonium.
Jax Pavan, a Jedi Knight, had formulated a strategy with I-5YQ and his other allies, initially conceived by Tuden Sal, to eliminate the Emperor. The rationale was that I-5YQ, being a droid, would have intentions undetectable in the Force, allowing him to approach Palpatine unnoticed and strike before the Emperor could react. Following considerable debate over the risky proposition, Jax and his companions ultimately resolved to proceed.
Darth Vader had persistently pursued Jax Pavan. Dejah Duare, a Zeltron, had become part of Jax's group within the Whiplash organization. This Zeltron enjoyed experiencing the sensations of the Force. Pavan, conversely, distanced himself from her. She found the opposite with Probus Tesla, an Imperial Inquisitor, and subsequently betrayed Pavan.
Laranth Tarak was escorting Kajin Savaros to Whiplash headquarters when they were ambushed and taken prisoner by Imperial forces. Darth Vader subjected Laranth to torture and erased Kajin's memories. He then manipulated Kajin to turn against the Jedi, convincing him that he was a Sith.
Upon learning of Laranth and Kajin's capture, Jax declared that their assassination mission had transformed into a rescue operation. Jax discovered that Laranth was being detained at the ISB Central Office. After deliberation with Whiplash, Jax contacted Vader and proposed an exchange. They would surrender I-5YQ, also a target for Vader, in exchange for Laranth Tarak.
I-5YQ was escorted into the facility by Dejah Duare and Haninum Tyk Rhinann. They were greeted by three Inquisitors who led them to the detention area where Laranth was held. There, they encountered Darth Vader, Kajin Savaros, and Emperor Palpatine himself. However, I-5 made no attempt to attack the emperor, and Palpatine vanished, revealing himself to be merely a hologram. Vader then inquired of Dejah which of them possessed the bota. She claimed ignorance, suggesting that I-5 might have given the vial to the Jedi. She pointed to one of the Inquisitors, who was actually Jax in disguise. Jax and his allies were stunned by her betrayal, and she explained that her actions were not motivated by politics or personal gain, but by her enjoyment of experiencing the Force, and that Inquisitor Probus Tesla did not have the same moral constraints as Jax, which prevented them from truly connecting.
Vader demanded the bota from Jax, but the Jedi Knight did not have it. Vader instructed Jax to compel I-5 to surrender the bota. I-5 responded that he did not possess it, and then fired his lasers at Vader. Vader, however, sensed the droid's intentions through the Force, confirming that I-5 had developed some degree of sentience, and was able to deflect the shots with his hand. When no one would relinquish the bota, Vader Force-slammed Jax against a nearby wall. Laranth ultimately relented and revealed that she held the bota. Vader seized it and then forced Jax to hand over the pyronium nugget he had given him in the past. He then requested Darth Ramage's holocron, the Sith holocron containing information on combining the effects of pyronium and bota. However, Jax no longer possessed the holocron. Vader stated that it was inconsequential and proceeded to take the bota, injecting the serum into himself via the receptacle on his chest plate, despite a last-ditch objection from Tesla.

Initially, the bota seemed to have little effect on Vader. Then, he abruptly lost control. Jax determined that this was the moment to strike Vader and ignited his lightsaber. However, Vader began unleashing Force energy in all directions, completely uncontrolled. One of his blasts caused a durasteel frame to collapse onto I-5, trapping the droid. Another struck the EMP field that had been disrupting Laranth's Force-sense. Now uninhibited, she moved to shield Kaj. Everyone sought cover except for Dejah, who reveled in experiencing the Force. She was soon struck by one of Vader's Force energy blasts and slammed against the wall, resulting in her death. Another blast killed the second inquisitor as well.
Laranth attempted to use the Force to conceal Vader, but her efforts were futile. I-5 began using his lasers to break free from the door. Jax cautiously approached the Sith Lord, but Probus Tesla intercepted him and engaged him in combat. Tesla was then grazed by one of Vader's blasts and knocked away. Jax then attacked Vader with his lightsaber, but the blow merely ricocheted off the Force surrounding the Dark Lord, and the lightsaber was dislodged from Jax's hand as he was knocked to the ground.
At that moment, a Whiplash strike team led by Thi Xon Yimmon stormed in. Tuden Sal was among the members, and he attempted to escort Kajin to safety, but the boy broke free and charged toward Vader. Vader ensnared him with the Force and sent him hurtling toward an open window. Jax moved to assist the boy, but Vader also ensnared him with the Force.
Rhinann, who had been observing from cover, could not bear to see Vader exhaust the last of the bota. His final opportunity to touch the Force was slipping away. He attacked the Dark Lord, leaping onto him and attempting to dismantle his breathing apparatus. Vader lost his grip on Jax and Kajin and stumbled out the window with Rhinann in tow. They collided with the ground after a significant fall, and for a fleeting moment, Rhinann touched the Force, feeling it surge through him as he died.
Back in the control room, Jax noticed that Tesla had vanished. There was a surge of Force energy from the hangar, and the building began to explode. Jax swiftly gathered the pyronium and his lightsaber and fled to safety.
Following the encounter, Jax and Laranth reflected on numerous matters, and Jax questioned whether Vader was indeed Anakin Skywalker. Den Dhur, a member of the strike team that had come to their rescue, rejoined Jax and his companions, and the group resumed their work with Whiplash.
Darth Vader and Probus Tesla both survived, although Tesla's subsequent fate remains unknown.
This battle was conceived by author Michael Reaves as the concluding confrontation in the Star Wars: Coruscant Nights trilogy. Despite the cover of Coruscant Nights III: Patterns of Force depicting Vader and Pavan engaged in a lightsaber duel, the two never actually engage in such a duel.