The Jedi rushed at Vader with his skill Ataru (the 4th form, based on fast, strong attacks). Vader was struck twice before he could even realize what was happening.
Vader countered through a combination of force pushes and using his grip to hit the Jedi against the wall. Vader knew he was at a severe disadvantage without a lightsaber. He could continue using the Force and hit the Jedi, but he knew he wasn't as good as he was before. He would also tire out quickly if that was his only attack.
Suddenly the Jedi appeared before him and tried to make a strike on his armor. Vader stopped the lightsaber an inch from his heart, using tutaminis (the force ability to absorb energy) to hold the lightsaber in place.
"You're very powerful," says Vader.
"What did you say?" asks the Jedi.
"You can join me, become my apprentice, and together we can take down the emperor."
"I will never join you. As a Jedi Knight of the Galactic Republic, I WILL NEVER SUBMIT TO THE DARK SIDE!"
"Very well, then Jedi Knight, that was your last chance to live."
Vader, right then, noticed a second lightsaber on the Jedi's belt. He reached into the force and took it. He turned it on.
It was blue. Vader knew this was his only chance. He immediately started clashing with the Jedi. Even with the lightsaber, he wasn't able to overpower the Jedi. They were equals in strength, but not in speed.
With his clunky armor, it was difficult to gain any speed, but Vader was compensating in strength.
Clash after clash occurred as they both inched upwards through the building. Vader slashed to the left and the Jedi hit it down, using the momentum to gain an extremely high jump.
"You've lost, Sith Lord. I will defeat you."
Then, he used the force to become a blur. He was moving so fast, Vader could not see him.
***This Jedi is Kal Ette (NOT REAL, just for the fanfic), a Jedi Knight who learned under Jedi Master Djinn Altis. He is a master of force speed (that is, using the force to make yourself much faster and more agile). He was a practitioner of the Ataru form, which he could use to good effect as seen in this battle. He was also good at using Djem-So, the 5th form. He could blend both styles together, forming a dangerous combination of moves. ***
Vader looked all around and could not see him. He heard a zoom of sound and suddenly there was a pain in his shoulder. When he looked, he saw nothing. He heard another zoom and rolled out of the way just as a green light flashed where his heart had been moments before. He deactivated his lightsaber and reached into the force to find the Jedi. To his surprise, he was able to find the Jedi. He immediately grabbed him using the force and brought him to the center and slammed him into a wall.
The Jedi immediately got up and countered Vader's clunky Djem-So using the huge leaps of Ataru and tried to hit Vader from behind. Vader, suspecting this, immediately blocked his back and turned around to face the Jedi.
'This is becoming irritating very quickly,' thought Vader, frustrated and starting to become tired.
The Jedi was also becoming tired. His attacks were becoming a little bit slower. Ataru used too much energy for the body to compensate. Eventually, the Jedi would become tired and unable to fight. If Vader could prolong the fight for just long enough, he could win.
Maybe the Jedi knew it too, for when Vader slashed to the right, he hit it down and tried to jump away. However, Vader, wise to this trick now, used the force to grab the Jedi and slam him into the ground.
The Jedi got up and the fighting started again. Clash after clash, slash after slash. Vader was finally able to equalize with the Jedi in speed, due to the Jedi's exhaustion, and used it to continue the fight. The Jedi used the force to push Vader, but Vader reciprocated, causing quite a similar situation as that on Mustafar. Neither could gain an inch on their force push and eventually jumped back.
Every strike the Jedi tried was in vain, as it was always met with a block from Vader. The Jedi's 4th form mastery was now, finally, betraying him. His exhaustion was apparent, with each strike becoming lighter and slower.
Vader pushed his advantage, hard. Vader swung his lightsaber using his Djem-So training. The Jedi was barely able to move out of the way in time. The Jedi tried, again, to jump, but Vader, again, used the force to slam him down.
"It's already over," says Vader, "You've already lost. There is no more need to fight."
"Only over my dead body will I surrender to you," says the Jedi.
"So be it," says Vader, frustrated at the Jedi's stubbornness, "You will die."
Their lightsabers simultaneously lock together. Vader immediately overpowered and disengaged the lightsaber lock. He immediately started a flurry of hits; the Jedi was barely able to block them. After this, the Jedi fell to his knees. Out of energy and knowing that the battle was lost, he sat down and meditated.
"It was a tough battle, Jedi," says Vader, exhausted, but relieved at the end of the battle, "You have my respect for that."
"Thank you," says the Jedi, "Now kill me and get it over with."
Vader obliged and put the lightsaber through his chest, finally ending the rebellion and claiming himself a lightsaber. The Jedi fell to the floor, lifeless, and Vader looked at him for a few seconds, thinking of the battle.
Vader walked out and looked at his suit. There were holes everywhere in his cape, his shoulder pads were hanging on by a thread, and the metal on his legs was showing.
"My Lord, we have crushed the rebellion," says an imperial commander, "They have lost all their soldiers."
"Very good, commander," says Vader.
"What do we do now, about this planet?" asks the commander.
Vader looks at him and replies, "Keep a permanent imperial presence on this planet, to ensure there are no more rebellions."
Then, Vader walks away and into the ship thinking of how to turn this lightsaber red.