Work Text:
Leia breached the idea, of course. Leia, the strong-willed, quick-tempered twin, though physically weaker, had never gotten on with Vader. They were too much alike.
Luke and Leia's father, while not possessed of an ounce of patience, tact or subtlety himself, required large doses of those in his progeny.
He whipped his daughter for her disrespect and disobedience til she bled, powerful strokes against her naked back, ass, and thighs. He never touched her sexually, probably never even looked at her that way, but the pain of the beating and the humiliation of his frigid blue eyes seeing her naked body was enough to make her burn with lust, to want him - this beautiful, powerful, perfect man - more than anything else in this world ever since she was old enough to understand such things.
Luke had been their father's favourite ever since he was old enough to run. Lord Vader saw his son - with his blue eyes, and his fair hair, and a mild temper - as an extension of himself, taught him to fence, and to ride, and the intricacies of military theory and of the dark sorcery he himself practiced. They boy, in turn, and admired him, accepted his teaching with pure fascination and his every decision without a question. Only once, in his teenage years, Luke had spoken out against his father, begged him - upon bended knee - for mercy on Leia, who had managed to anger the ever-volatile man yet again. He only succeeded to make her punishment harsher.
Vader had been a general, a blacksmith's bastard son raised to the title of lord and a position of power through countless wars, and at war he died.
Luke ambushed him, struck him down with the sword Vader himself had given him, then wept like a child as the Sorcerer suffocated to death, coughing up blood from a lung wound. He loved his father, loved him so much that it broke his heart, but it had to done. Vader, a tyrant, a hero, a murderer, a genius and maniac of war, was too dangerous to be left alive.
Leia seduces her brother shortly after their father's funeral. She slips into his bed for warmth, steals his kisses under the guise of comfort, ruts against his fingers.
Spawning a child with their tainted blood is unthinkable. He fucks her in the ass instead, licks her cunt afterwards to make her come, even when she's bleeding.
Neither Luke or Leia ever have children. Leia marries, but is soon widowed, losing her husband in a tragic hunting accident. She dies shortly after, succumbing to a swift but painful disease that she believes to be God's wrath, a punishment for incest and devilish sorcery.
Luke becomes a monk to atone for his own sins and his sister's, lives to an old age, an abbot, widely respected for his wisdom and piety, his ascetic way of life and prophetic visions, almost a saint.
They are buried in the chapel of the imposing yet austere Vader Castle, side by side in a manner more befitting of husband and wife, less than four paces from their father's monumental black sarcophagus.