Inko doesn't move. She doesn't speak. She just stands in the doorway, tears carving silent tracks through the shock on her face, her knuckles white where they grip the doorframe. Katsuki watches her. His own breathing is still heavy, his cock slick and softening against Izuku’s thigh where he holds his son against his chest. The silence stretches, thick and hot with the smell of sex and betrayal.

“See?” Katsuki says, his voice a low rumble in the ruined quiet. “She’s not leaving.”

Izuku trembles against him, a fine, full-body shiver. He turns his head, his green curls damp with sweat, to look at his mother. His eyes are wide, glazed, but there’s a new clarity in them now. A terrible, possessive understanding.

“Mommy’s still watching,” Izuku whispers, the words a breath against Katsuki’s skin.

“Yeah.” Katsuki’s hand slides from Izuku’s back, down over the curve of his ass, possessive and claiming. He doesn’t look away from Inko. “She didn’t get enough. You gave her a show, baby, but she wants an encore.”

Izuku’s breath hitches. He pushes back slightly against Katsuki’s hand, his body already responding, the slick heat of him making a fresh, wet smear on Katsuki’s thigh. “She wants to see more?”

“She’s not moving, is she?” Katsuki’s other hand comes up, fingers tangling in Izuku’s hair, turning his son’s face to look at Inko directly. “Tell her what you want, Izuku.”

Izuku’s lips part. He stares at his weeping mother, at the woman who raised him, and his voice comes out soft but utterly certain. “I want to show you, Mommy. I want to show you how much I love my daddy.”

A choked sob escapes Inko. She shakes her head, a tiny, frantic motion, but her feet are rooted. Her eyes are locked on them.

“See?” Katsuki murmurs, his mouth against Izuku’s ear. “She’s listening. Tell her the rest.”

Izuku swallows. His hand comes up, small and freckled, to cover Katsuki’s where it grips his hip. He looks right at his mother. “Daddy isn’t yours anymore. He’s mine. He belongs to me.”

Izuku pushes away from Katsuki’s chest, his movements deliberate now, his eyes never leaving his mother’s shattered face. His fingers find the hem of Katsuki’s oversized shirt—the one he’s been wearing—and he pulls it up and over his head in one smooth motion, letting it drop to the floor along with the skirt. The lamplight catches the full, pregnant curve of his belly, the soft swell of his chest, the dark pink of his nipples, hard and puffy. He doesn’t hesitate. He sinks to his knees on the rug, right between Katsuki’s spread legs.

“He said no for years, Mommy,” Izuku says, his voice soft but clear as his hands go to Katsuki’s softening cock. He wraps his fingers around the thick, slick base, starting a slow, firm pump. “Every day. He told me it was wrong. He told me to stop looking at him like that.”

Katsuki lets out a low groan, his head tipping back as Izuku’s hands work him, feeling him swell and thicken anew under his son’s touch. His own hands come to rest on Izuku’s curls, not guiding yet, just resting there, possessive.

“But I didn’t stop,” Izuku continues, his gaze locked on Inko. He leans forward, his breath hot against the head of Katsuki’s cock. “I joined his team. I wore the uniform. I made him look. I begged him. He didn’t break until camp.”

Inko makes a sound, a wet, broken gasp. She shakes her head again, but her eyes are wide, unblinking, drinking in the sight of her son on his knees, her husband’s massive cock filling his hands.

“It’s true,” Katsuki grunts, his voice rough. His hips give a slight jerk into Izuku’s grip. “Fucking stubborn brat. Wouldn’t take no for an answer.”

Izuku’s lips curve into a small, triumphant smile. He opens his mouth, his tongue darting out to lick a broad stripe up the underside of Katsuki’s shaft, collecting the mixed slickness of their previous climax. Then he takes the head into his mouth, sucking gently, his cheeks hollowing.

With his other hand, Izuku reaches between his own thighs. His fingers slide easily through the wetness there, a soft, slick sound in the quiet room. He pushes two fingers inside himself, his breath hitching around Katsuki’s cock. A low moan vibrates against Katsuki’s skin.

“See how easy I am for him, Mommy?” Izuku murmurs, pulling off with a wet pop. He pumps Katsuki’s cock with his fist, staring up at Inko as he fingers himself deeper. “I’m always ready. Always wet. Just for Daddy.”

“Enough talking,” Katsuki growls, his patience snapping. The fingers in Izuku’s hair tighten, fisting. He guides his son’s head back to his cock, not gently. “Show her.”

Izuku opens his mouth obediently, taking Katsuki in deeper this time. Katsuki doesn’t let him set the pace. He holds Izuku’s head still and thrusts upward, a hard, shallow push that makes Izuku gag, tears springing to his eyes. The sound is obscenely wet.

“That’s it,” Katsuki says, his voice a dark rumble. He looks over Izuku’s head, directly at Inko. His hips begin a relentless, punishing rhythm, fucking into Izuku’s throat. “This is what he wanted. This is what he is.”

Katsuki’s hips piston, driving his full length into Izuku’s throat with a wet, rhythmic slap of skin. Izuku gags, a choked, guttural sound, tears and saliva streaking his flushed cheeks. His own fingers work frantically between his legs, plunging in and out of his soaked cunt, the slick noise a counterpoint to his choked moans.

“We didn’t fuck until camp,” Katsuki grunts, his gaze locked on Inko’s paralyzed form. He pulls Izuku’s head back by the hair, letting his son gasp for air, cock glistening and brutal against his lips. “Months of him begging. Months of me saying no. Then we got to those cabins and he broke me.”

Izuku whimpers, diving back onto Katsuki’s cock before he’s fully caught his breath, taking him deep. His green eyes roll back, blissful even as he chokes.

“Fucked him in the lake,” Katsuki continues, his voice a dark, steady narration. He thrusts up, holding Izuku impaled. “On the dock. In the woods where anyone could’ve seen. Your son’s a fucking exhibitionist, Inko. Couldn’t get enough.”

Inko’s hand flies to her mouth, muffling a sob. She doesn’t move from the doorway.

“Then we brought in Kirishima,” Katsuki says, a cruel smile twisting his lips. He watches Inko’s eyes widen. “Yeah. His coach. Had him watch. Then had him join. Your boy took us both, Inko. Two cocks at once. Screamed for it.”

Izuku moans around the thick flesh in his mouth, his hips bucking against his own hand, his pregnant belly quivering.

“Found out he’s a piss slut, too,” Katsuki says, the words deliberate and filthy. He yanks Izuku off his cock again. “Aren’t you, baby? Tell her.”

Izuku pants, drool stringing from his chin. He looks at his mother, eyes dazed with lust. “Daddy… Daddy marks me inside. All the ways. I drink it. I love it.”

“You raised a whore,” Katsuki states, flat and final. His hand strokes Izuku’s hair, a grotesque parody of tenderness. “A beautiful, desperate little whore who only comes alive when he’s full of his father’s cock.”

Katsuki’s cruel smile widens. He looks down at Izuku’s tear-streaked, worshipful face. “You said you love it when I mark you. Let’s show her.”

He doesn’t give a warning. A low grunt escapes him, and a hot, golden stream arcs from the head of his still-hard cock, splashing across Izuku’s forehead, his closed eyes, his open, panting mouth.

Izuku gasps, but he doesn’t flinch away. He tilts his head back, his tongue darting out to catch the bitter, salty flow. He swallows, his throat working, as the piss runs in rivulets down his freckled cheeks, over the swell of his pregnant belly.

“Oh, god,” Inko whimpers from the doorway, her voice a shattered whisper. Her knuckles are white where she grips the doorframe.

“Watch,” Katsuki commands her, his voice a dark rumble. He shifts his aim, the stream painting Izuku’s chest, soaking his hard, puffy nipples, dripping down between the curves of his small breasts. “This is what your son is. Mine. To use. To ruin.”

Izuku moans, a raw, desperate sound. His hands fly to his own chest, smearing the liquid into his skin, pinching his wet nipples. “Daddy… more…”

“Greedy,” Katsuki murmurs, but he obliges. The stream weakens, trickling now, pattering against Izuku’s trembling thighs before he gives his cock a rough shake, the last drops spotting Izuku’s flushed skin. The room smells sharply of ammonia and sex.

Izuku leans forward, pressing his face against Katsuki’s thigh, nuzzling into the damp fabric. “Thank you,” he breathes, his voice muffled. He looks up at his mother, his green eyes blazing with a terrible pride through the wet mess on his face. “He marks what’s his, Mommy. Every way he can.”

“Get on the desk,” Katsuki says, his hand fisting in Izuku’s curls to pull him upright. “On your back. Legs open. Let her see everything.”

Izuku scrambles to obey, his movements clumsy with urgency. The polished mahogany is cool against his heated skin as he lies back, his pregnant belly a pronounced curve. He spreads his legs wide, heels digging into the wood, presenting his soaked, swollen cunt to the room—and to his mother’s horrified gaze.

Katsuki stands over him, a massive silhouette in the lamplight. He strokes himself, his cock glistening and fully hard again. “You see that, Inko? Look how open he is. How ready. He’d let me do anything. And he has.”

“Please,” Inko whispers, the word barely audible. “Katsuki, stop this.”

“You had your chance to stop it,” he says, not looking at her. His eyes are on Izuku’s body. “You opened the door. You stayed. This is your choice.” He places the broad head of his cock against Izuku’s entrance, not pushing, just resting there. Izuku shudders, a full-body tremble of anticipation.

“Tell her what you want now,” Katsuki says, his voice dropping.

Izuku turns his head, his cheek against the cool wood. He looks directly at his weeping mother. “I want Daddy to fuck his baby into me again. Right here. While you watch.”

Katsuki pushes inside him.

It’s not a gentle slide. It’s a brutal, claiming thrust that sheathes his full, thick length in one punishing drive. The wet, obscene sound of his cock splitting Izuku open fills the silent study. Izuku’s back arches off the desk, a choked scream tearing from his throat, his hands scrabbling at the polished wood.

“There’s my whore,” Katsuki grunts, his voice raw. He doesn’t move, just lets Izuku feel the impossible stretch, the burn. “This what you wanted? Huh? Your mother watching me wreck this pretty cunt?”

“Yes!” Izuku sobs, his body trembling violently around the invasion. “Daddy, yes!”

Katsuki pulls back and slams home again. The desk groans. He sets a ruthless, deep rhythm, each thrust jolting Izuku’s body, making his pregnant belly quiver. “Say it. Tell her what you are.”

“I’m your slut!” Izuku cries out, his head thrashing. “Your—ah!—your desperate little whore!”

“Louder.”

“I’M YOUR WHORE!” Izuku screams, the words echoing off the leather-bound books. His eyes are screwed shut, tears leaking from the corners, his mouth slack with pleasure-pain.

Katsuki leans over him, one hand braced by Izuku’s head, the other gripping his hip hard enough to bruise. His thrusts become shorter, harder, aimed deep. “Made for this. Born for it. My cock’s the only thing that makes you real.”

Izuku can only nod, gasping, his own hands flying to his chest to pinch and pull at his wet, sensitive nipples. “Only yours, Daddy, only—fuck!”

Inko makes a wounded animal sound in the doorway. Katsuki’s head snaps toward her, his hips never stopping their brutal pace.

“You hearing this?” he snarls at her. “Your son. Begging for his father’s dick. He’d let me do this on the fucking fifty-yard line if I wanted.”

“Please,” Inko whimpers, fresh tears streaming down her face. “He’s pregnant, Katsuki, you’ll hurt the—”

“The baby’s fine,” Katsuki cuts her off, driving into Izuku with a particularly vicious snap of his hips. Izuku wails, his legs wrapping around Katsuki’s waist to pull him deeper. “Feels his daddy, too. Knows who owns this body.”

He changes his angle, grinding deep, and Izuku’s eyes fly open, a broken, continuous moan ripped from his chest. “Right there, right there, please, Daddy, don’t stop—”

“Gonna come?” Katsuki pants, sweat beading on his temple. His rhythm is starting to fracture, going harder, faster. “Gonna squirt all over my desk with your mommy watching?”

“Yes! I’m gonna, I’m gonna—”

“Do it. Show her what a mess you are for me.”

It hits Izuku like a seizure. His body bows, every muscle locking tight. A raw, shattered scream tears from his throat as his cunt clenches violently around Katsuki’s thrusting cock, and then a hot gush of liquid soaks between them, pattering against the wood below with a sound like rain. He squirts in pulsing waves, his vision whiting out.

Katsuki fucks him through it, through the trembling aftershocks, his own control snapping. With a final, guttural roar, he buries himself to the hilt and pumps his release deep into Izuku’s clutching heat, his hips jerking with each pulse.

For a long moment, there is only the sound of their ragged breathing and the wet drip from the edge of the desk.

Katsuki slowly pulls out. Izuku whimpers at the loss, his spent body going boneless against the wood. Katsuki looks down at the mess—the come leaking from Izuku’s reddened entrance, mixed with slick and piss and squirt, all pooling on his mahogany desk. He looks at Inko.

“He’s mine,” Katsuki says, his voice hoarse but absolute. “You don’t get a say. You don’t get a choice. You just get to watch.”

Izuku turns his head, his green eyes hazy and sated. He smiles, a soft, terrible thing, at his mother. “See, Mommy? He belongs to me now.”

Katsuki’s harsh breathing slowly evens. He looks down at Izuku, whose eyes are half-lidded and glazed, his body a limp, wet mess on the ruined wood. The rage and performance drain from Katsuki’s face, replaced by something quieter, more possessive. He leans down, his movements suddenly gentle, and slides his arms under Izuku’s back and knees.

“Alright, nerd,” he murmurs, his voice a rough scrape. “Let’s get you to bed.”

He lifts Izuku easily, cradling him against his chest. Izuku’s head lolls against Katsuki’s shoulder, a soft sigh escaping his lips. Katsuki bends his head and presses a kiss to Izuku’s sweaty temple, lingering there for a moment.

He turns, holding his son, and faces Inko. She hasn’t moved from the doorway. Her face is a mask of tear-streaked shock, her hands clenched in the fabric of her dress.

“Master bedroom’s ours now,” Katsuki states, his tone flat, final. “You’re welcome to stay. Or leave. Don’t fucking care anymore.”

He doesn’t wait for a response. He walks past her, Izuku’s bare, damp skin glowing in the low hall light. The scent of sex and sweat and them trails behind him.

Inko’s voice is a broken thread. “Katsuki… he’s my son.”

Katsuki stops but doesn’t turn around. Izuku stirs in his arms, nuzzling closer. “He’s mine,” Katsuki says, without heat. It’s just a fact. “He told you. You watched. Figure it out.”

He carries Izuku down the hall, pushes their bedroom door open with his foot, and kicks it shut behind them. The familiar space is dark and cool. He lays Izuku carefully in the center of the large bed.

“Daddy?” Izuku whispers, his hand reaching out blindly.

“Right here.” Katsuki strips off his own soiled shirt, then grabs a soft washcloth from the en suite. He runs it under warm water, returns, and begins to clean Izuku with a methodical tenderness. He wipes the drying come from his thighs, the slick from his belly, pats gently between his legs.

Izuku watches him through heavy eyes. “She saw everything.”

“Yeah.”

“Do you think she’ll leave?”

Katsuki tosses the cloth aside and stretches out beside him, pulling the covers over them both. He gathers Izuku against him, one big hand splayed over the curve of his pregnant stomach. “Don’t know. Don’t care. Only thing that matters is you’re here. With me.”

Izuku turns in his arms, his green eyes searching Katsuki’s face in the dark. “You mean it? You’re not… ashamed?”

Katsuki’s thumb strokes over Izuku’s hipbone. “Was never ashamed of you. Just of wanting you. Not anymore.” He leans in, capturing Izuku’s mouth in a slow, deep kiss. It’s not hungry or desperate. It’s a claiming of a different kind. “You’re mine. My boy. My mess. My future. Everything else is noise.”

Izuku melts into the kiss, into the words. When they part, he rests his forehead against Katsuki’s chest. “I love you, Daddy.”

“Love you, too.” Katsuki’s voice is gruff. He shifts, settling them more comfortably. “Now sleep. You’re exhausted.”

Outside the door, in the silent hall, there is only the sound of muffled weeping, and then, eventually, the soft click of the front door closing.