Obi-Wan jumped backwards, parrying Vader's blow with his lightsaber. They traded swings for a few moments before breaking apart. They began to circle each other for a moment.
"You could never defeat me, Obi-Wan. I was always better than you," Vader said, trying to distract the Jedi.
"You were too arrogant, Vader. Too wrapped up in yourself. You are not the greatest Jedi ever."
"You're right about that. I'm far more than just a Jedi."
"Right, you're a Sith lord," Obi-Wan spat. "The scum of the galaxy."
Vader replied with a lunge at the Jedi's throat. Obi-Wan stepped nimbly aside and parried the blow before waltzing to Vader's other side. Vader turned to face him, and Obi-Wan could feel the anger radiating from him. It was nauseating.
"Where is she?" Vader asked, swinging his saber portentously.
"Where's who?" Obi-Wan asked, beginning to circle Vader again.
"You know very well who. Padme, my wife."
Obi-Wan smiled uncharacteristically cynically. "Your wife? Padme was the wife of Anakin Skywalker. But as you said, Anakin no longer exists, so how can he have a wife?"
A fresh surge of hate radiated from Vader, but Obi-Wan also felt a bit of regret. "You're right, you know," Vader said, his voice softening almost unobtrusively. "She was the wife of Anakin Skywalker. But it's not her that I want. It's the child she carries within her. And although he too may be of Anakin Skywalker, I've come to claim him."
A wave of anger ran through Obi-Wan. "And what would you do with him? Turn him, use him? Do you think the Emperor would allow him to live? Do you believe that the Emperor would allow a Skywalker to live? No! He would kill the child the first chance he got." Obi-Wan shifted his saber, pointing it to the ground. "Even Vader could not be that cold-hearted."
Vader stepped toward him, pointing his saber to the ground as well. "And what would you do with the child, Obi-Wan Kenobi? Train him in your foolish Jedi ways? Raise him to someday kill me and bring the Jedi back to power?"
"I would never use a child like that."
"Like you used me? You thought you could train the great 'chosen one'. And doing that would forever have the Council eating out of your hand."
"I trained you because it was Qui-Gon's dying wish!" Obi-Wan shouted.
This put Vader off for a moment, but he soon recovered and lunged again. This time he fought with a fever, wishing for nothing more than to rid the galaxy of the one man who could make him regret his decision. The one man who had ever truly tried to understand him. The only man who could make him feel guilty.
The intensity of Vader's attack startled Obi-Wan, and he was barely able to block some of Vader's blows. Obi-Wan slipped on a loose rock and nearly fell to the ground and was barely able to catch himself. He felt a searing pain across his arm and stumbled into a cliff wall. He looked down at his arm. A large gash worked its way now across his arm, blurring his vision with the pain. Vader stepped back with his saber raised, exuberated at the fact that he had wounded his opponent.
But Obi-Wan looked up at him defiantly and grasped his saber tightly with his good arm. He leapt over Vader's head and attacked. The Jedi's attack surprised Vader, but it was obvious that the wound was weakening the Jedi.
Soon, Vader took advantage of this and kicked out at the Jedi, sending him sprawled out on his back. Vader stood over the now unarmed Jedi, who looked up at him with regret, not fear.
"I had thought you would be a great Jedi, Anakin. But now I see that helping people was not the thing for you. You've chosen evil over good, willingly. Live with that. Let your son live with that," Obi-Wan said, accepting the fact that he was about to die.
Vader stared down at him for a moment, saying nothing. Finally he raised his lightsaber over his head and prepared to gouge his former Master. But he froze again, looking into the Jedi's eyes. He didn't see fear, as he wanted. But instead he saw repentance and acceptance. Obi-Wan wasn't afraid to die, he was just sad that he was going to now.
Vader lowered his saber, but kept it pointed at the fallen Jedi. He looked around at the canyon wall, spotting Padme as she stuck her head out of the little cave to watch the fight. He saw horror on her face, horror and fear for her friend. She looked away from Obi-Wan for a moment to look at Vader. Her eyes showed regret, fear, and sadness. And for the first time in months, Vader felt afraid.
He was afraid that if he killed this man, the woman he still loved would never be able to forgive him. Never be able to look at him again. Could he, Darth Vader of the Sith, live with that?