Fugaku is the name of Sasuke and Itachi's father. Mikoto is their mother.
Sins of the Father by Ouvalyrin
Fugaku remembers his first son with pride. He chooses Itachi's name himself, wanting nothing more than to train him in his image (be the son he himself had been unable to become). Itachi is quiet as a child and shows signs of intelligence even at a very young age. By the time he's ten months old he can throw a kunai with startling accuracy, and Fugaku takes pride in Itachi's accomplishment as if it is his own (Mikoto remembers the way his eyes shine and his mouth curves up in the barest hint of a smile as he tells her, and how Itachi looks faintly pleased, but that had been before Itachi killed for the first time).
Itachi is everything Fugaku has ever wanted to be, and he is everything he wants in a son. Itachi is perfection itself, and he does not realize then that this should scare him.
Itachi is ten when he kills his first man. It is on a mission, and it should disturb Fugaku how easily his son accepts the responsibilities of an adult, but all he can see is his son's name on everyone else's lips, and the admiration and awe in their eyes.
It does not occur to Fugaku that he should have told his son about killing someone. Itachi is a genius; surely he would have understood. He lies awake all that night, waiting for Itachi to return home, and he is vaguely aware that Sasuke does so as well but—
It is only when he hears the sounds of a bath being drawn does he relax, and Fugaku is unaware of the smile on his lips as he sinks into sleep.
(And there it is, a quiet voice asking "Niisan" if he's all right, and the slightly lower voice answering, and this, this has to be some particularly strange dream because he can hear over the water Sasuke moaning and whimpering and his gasping little voice crying out in the silence, muffled by something large and heavy like a hand across the mouth but still escaping.
A dream, he tells himself and goes back to sleep.)
The next day at the breakfast table, Itachi asks him calmly what it feels like to kill someone.
Fugaku remembers the look on Mikoto's face, the stark horror in her eyes as both he and Itachi realize she has not known. Then the horror drops off, sliding from her eyes and dripping onto the tablecloth where it dries into nothing. Sasuke looks between them, barely comprehending his brother's words but sensing the change in the air.
"Nothing," Fugaku tells him, thinking that this is what a genius must feel when he kills someone. Someone like Itachi would feel nothing at death, and for the first time he begins to see that his son might be a little fucked up. "You get used to it, after a while."
Itachi is silent. "I see," he says at last, and returns to his rice, eating methodically. He finishes and lays the chopsticks down with a soft 'clack.' "May I be excused?"
Fugaku nods at him. "You may go," he says, and something in his chest feels heavy. Sasuke stares at his rice and picks at it, a small frown tugging at his lips. Fugaku looks at him for the first time, sees just how terribly small Sasuke is, and how easy it would be for even a shinobi of average strength to overpower him. He stares after Itachi's retreating back and realizes—
Itachi is not the son he wanted, but there is nothing he can do about that now.
Fugaku is a father of two sons, and he watches them both closely over the next few weeks. For the first time he notices how Itachi rarely interacts with others in his age group. His only friend is Shisui, and outside of him there is only Sasuke, who is the exact opposite. Fugaku wonders why Sasuke's laughter sounds so foreign to his ears, and why he has never seen Sasuke's smile so bright and happy. Itachi never smiled, he remembers, Itachi rarely showed any emotion at all.
(Fugaku begins to wonder which brother truly is the stronger one, but tells himself it's Itachi, of course, Itachi his prized child, and not Sasuke, who he has never noticed before. He has two sons, he knows this, but he only has eyes for one.)
He thinks Itachi knows he's watching, and that is why it shocks him when Itachi leans down close to Sasuke, nearly eye level with his larger body blocking him from sight, and kisses his younger brother.
Fugaku's fairly sure it's on the lips as well, and disgust and horror run through him. He decides it must be Sasuke's fault for distracting him, distracting Itachi from becoming the son Fugaku so desperately wants, and that day he tells Itachi to stop seeing Sasuke.
Itachi stares at him mutely. They are the same height now—when did that happen?
"Very well, Father," Itachi tells him, and Fugaku cannot help the shiver of fear that comes with Itachi's deepening voice.
This is my son, he thinks, but cannot explain why he's so relieved at Itachi's obedience.
He cannot remember when he decides at last that Itachi is dangerous. He tells this to Mikoto and she says nothing, her eyes downcast and focusing on her hands. The perfect wife,he thinks.
"What is Sasuke's favorite food?" he asks her suddenly, thinking that if Itachi cannot be his son he will have to mold Sasuke instead. The boy is already so desperate for his attention after all, it wouldn't be hard. He finds he cannot remember Sasuke's birthday, nor the day he was born. He wonders: when did I lose my family?
Mikoto stares at him in surprise. He can see the hope in her eyes, shining softly like tears, and he longs to touch her skin. But they are Uchihas, and affection is not their way.
"Tomatoes," she replies. "He likes tomatoes."
That night, Fugaku cannot ignore what Itachi does. He stands in the shadows, watching, and as regular as clockwork Sasuke's door slides open and he goes slipping into the night. He has become quieter than Fugaku remembers him, stealthier, though he is still far from Itachi's skill level at his age. He slides Itachi's door open with fumbling fingers, and Itachi's figure looms above him, and Fugaku wonders at the phrase darker than darkness that jumps into his head.
"Niisan?" Sasuke's voice is small, embarrassed and afraid.
"Not tonight," Itachi tells him gently, and in his voice is far more concern than Fugaku has ever heard him express. He lays hands on Sasuke's shoulders and moves as if to steer him back to his room, but then his eyes slide to where his father stands, invisible. Fugaku's heart leaps in his throat and he moves for his kunai, before remembering that this is his son and his son is not his enemy.
He thinks. He hopes. He prays.
"Please?" Sasuke has to tilt his head back to stare at Itachi, unable to see how Itachi's eyes probe the darkness, meeting Fugaku's challengingly. "I have—nightmares and I don't want to ask Father or Mother..." Fugaku's heart twists at this before he thinks, strength, that's what Sasuke's after, and the sudden, surprising warmth and approval welling up almost drowns out the pain.
Then...what could Sasuke have nightmares of? He thinks of childish fears, of monsters under the bed and in the closet, of the strange demons that only come out at night before dismissing them as unworthy.
"Very well, Sasuke. But this is the last time."
Sasuke's smile lights up his face and he hugs Itachi, and Fugaku suddenly thinks, I am his father, and is unprepared for the surprise he feels. Then the sliding door closes and Fugaku simply listens.
He closes his eyes to the sounds coming from within, too quiet for him to have heard from his room but easy from just outside. He wishes he could close his ears, and does not doubt that every sound wrung out is from Sasuke, and the last, deep, shuddering grunt from Itachi.
He has to stop this, and he thinks he might know how.
Fugaku stares up at Itachi, at the demon he never noticed his son has become, and all he can think is, I've failed.
And then everything is silent.