Vader observed the destruction he had caused with pride: where Alderaan used to stand, nothingness reigned over the particles and ghastly remnants that floated in the surrounding atmosphere. And while others under Vader's authority had thought the destruction to be a necessary tactic with which to open the Princess' mouth, the self-proclaimed father had different intentions.
At last, thought Vader, the Princess is no longer bound to her unnatural guardians. She is mine, and mine alone -
The very same young woman was in his midst presently; she held a weakening stance at the edge of the Death Star, behind the window that had shielded her from committing an act that would have been her sacrifice for her planet.
Leia felt like dying. Only she would have preferred to have quit breathing before her eyes had watched the innocent murder of more people than she would have ever known.
And she was, above all, angry.
Angry with her life, with the damned Empire and the malevolent, unfeeling Darth Vader. Leia had no family now, as far as she knew; she yearned to be peacefully resting on a planet that no longer smiled - existed - in the intimidating galaxy.
"You must face the truth."
It was Vader, his command simultaneously piercing and energizing her to lash out at the Sith Lord. She growled in a low voice to her enemy, "Truth is seldom necessary."
She will hear the truth, no matter what her feelings are, decided Vader; he wanted to tell her, to surprise her for once, to break her. And it was not simply her fortitude that bothered him. She was on Obi-Wan's side, and this had infuriated him passionately. "It is unwise to be ignorant of the truth. You veil yourself from a greater destiny -"
"I don't want to hear any more from you," snapped Leia, turning to face Vader. "I deserve no more interrogations, after what you've done."
Her allegation frustrated Vader. "Do you sense nothing of our presences in this room? Your loyalty to the Alliance betrays your thirst for vengeance."
"On the contrary," the Princess replied coldly, "What destruction the Empire has caused can only invite me to seek vengeance."
Vader had begun to lose hope. "Then you cannot feel the Force."
"The Force?" shot Leia. "I am not a Jedi. And I forbid you to speak to me."
"What happened to your real mother and father?" pressed the Sith. "Dead after your birth?"
"I refuse to answer you -"
Suddenly the sliding door exposed the secrecy of their conversation, and in came an admiral. "Lord Vader, the Emperor requests that you join him in his quarters."
"Tell him I will be there," instructed Vader. The admiral nodded and quickly exited the room. Vader returned his gaze toward the black abyss outside the Death Star. "Time is not in favor of the Rebel Alliance, Princess. Soon, should the Rebels refuse to surrender, what happened today to Alderaan -"
"You wouldn't dare to say that name," cut in Leia, stepping a foot closer to the center of the room, where Vader was statue-like and patient. "The least you could do now is to free me from this hellish place your emperor has created."
"He is your emperor, too," reminded the Sith Lord admonishingly, "and I hope you learn to respect those who know the way to peace."
"What peace?" challenged the Princess, chuckling as she neared Vader yet a little more. "Shutting down billions of lives with explosive-carrying battle stations is the Emperor's plan for peace?"
Leia could not bear it anymore; her hands would not clench - as they should have done, for the bones in her body repelled this horrible robot-man. He's not a man at all, she realized, no matter how his voice sounds, no matter how his limbs appear.
She was glaring straight at him, her father (although she still did not know this), and Vader merely looked back at her, unbiased and without empathy. He recognized the form of her eyes above a nose he knew to be Padmé's, and the cheeks and the lips and the hair - he ached at this observation in particular - were all Padmé's also, all so familiar to Vader that he thought for a moment that he was still Anakin.
But as Leia continued in her callous and unwelcoming gaze upon the cloaked figure, Vader returned to his thoughts of greed. Her unnatural parents from Alderaan are dead. My present work is complete.
Then, once Vader had configured his intelligent mind in order to formulate a solution, he announced proudly to the Princess, "You will have your wish. Should anyone come to rescue you, I alone will not order any direct restraints. Return to your cell."
The tone he utilized could very well have been "Go to your room", but such a phrase was a part of an imaginary world - at least to Darth Vader née Anakin Skywalker - and so he thought nothing of it as his child (still he thought there was only one) exited the room obediently, albeit of her own will to get away from the man who had altered her life significantly.