The Duel in The Works was a lightsaber duel fought in The Works district on Coruscant primarily between Khrado Ragnos and Darth Vader.
Background[]
Having trained extensively in the deep and ancient arts of the Sith race, of which he himself was a member, Ragnos had been a practitioner of the dark side for a century, and was a powerful and deadly warrior. As such, he greatly resented the mysterious Darth Vader for taking the title "Dark Lord of the Sith", which Ragnos himself had claimed. Based on the traditions of the old Sith Empire, only a single individual could hold the title at a time, so Ragnos took Vader's claim as a personal insult. Determined to destroy the usurper and his Emperor, Ragnos prepared a trap for the Sith Lords on Coruscant.
After arriving on Coruscant from Wild Space, Ragnos set himself to observing both Vader and the Emperor. He noted with interest that the two made frequent visits to the LiMerge Power Building, and decided to spring his trap there. Lying in wait, he sensed the incredible dark side power fairly radiating from the building, but mistakenly assumed it was due to Vader's influence.
The Duel[]
When Vader and the Emperor arrived with a small detachment of the 501st Legion, Ragnos sprang out of concealment, lightsaber activated. Making short work of the first half-dozen stormtroopers, he flung the rest out into the air with a powerful Force push. Sending a blast of Force lightning at Palpatine to incapacitate him, Ragnos engaged Vader blade to blade. Vader was stronger and had a wider knowledge of the forms of lightsaber combat, but Ragnos was faster, so the fight was evenly matched.
Surprised, upon striking Vader, to discover that the so-called "Dark Lord" was actually a cyborg, Ragnos's disgust and contempt increased and he pressed the attack. So focused was he on Vader that the Sith did not notice Palpatine recovering and only managed to deflect a barrage of Force lightning from the Emperor on pure reflex. Stunned to discover that Palpatine, too, was a Sith Lord, Ragnos became less focused on victory and more on survival. Fear began to whisper in the Dark Lord's mind.
Using every trick and Force power he could think of, Ragnos nonetheless found himself outmatched. Alone, he imagined, he could have been a match for either enemy, but together they were too much for him. Singed by Palpatine's lightning and struck a glancing blow by Vader, Ragnos tried to flee by leaping over Vader to higher ground, but he was caught in the air by Vader's Force grip and struck down. Lightsaber slipping from his grip, the Dark Lord fell dead at Palpatine's feet.
Aftermath[]
Following his death, Khrado Ragnos's war helmet and lightsaber were taken by Palpatine to his treasure storehouse of Mount Tantiss on Wayland. There they remained for decades until recovered by Tak Sakaros.
Sensing his brother's death from across the galaxy, Sakaros vowed to kill both Vader and the Emperor. Though he came up with several plans and came close to attempting to assassinate Vader on Commenor, it would ultimately be Luke Skywalker who dealt with both Sith Lords.