The vestment case was cold and unforgiving against Izuku's stomach. Katsuki's thrusts drove his cheek against the polished wood, forcing him to watch the tears streak his own flushed face, the slack-jawed pleasure he couldn't hide. Each slam of hips was a punctuation to the silent prayer in Izuku's head—not for forgiveness, but for more. The reflection showed the truth: a boy undone, owned, and desperately wanting it.

"See it?" Katsuki’s voice was a low rasp against his ear, his hands braced on the case on either side of Izuku’s head, caging him in the mirror’s view. "See what you are?"

Izuku couldn’t look away. His own green eyes were glassy, his mouth open and wet. He watched the powerful flex of Katsuki’s abdomen behind him, the sweat-slicked shift of muscle with every deep, punishing drive. "I–I see."

"What do you see?"

"A sinner," Izuku gasped, the words punched out of him.

Katsuki’s hand fisted in his curls, yanking his head back to sharpen the angle. "Louder."

"A sinner!" Izuku cried, the sound echoing off the sacred vessels lining the shelves. "I’m a sinner, I’m—" His voice broke as Katsuki hit a spot that melted his bones, a white-hot burst of pleasure that ripped a sob from his throat. "I’m yours."

"You are." Katsuki’s pace didn’t falter, a relentless, wet rhythm that filled the silent room. His other hand slid around Izuku’s front, palm splaying over the flat plane of his binderless stomach, feeling the deep, internal impact of every thrust. "Mine to fuck on the altar. Mine to break in the bell tower. Mine to ruin right here, where they prepare the holy wine." He pressed his lips to the shell of Izuku’s ear. "Do you feel ruined, Izuku?"

Izuku could only nod, a frantic, helpless motion. Ruin was the ache of fullness, the raw stretch, the slick heat between his legs that was a constant, humiliating drizzle down his inner thighs. Ruin was the way his body clenched, greedy, every time Katsuki pulled back, begging for the next penetration.

"Use your words."

"Yes," Izuku whimpered. "Ruined. I feel it. Please—"

"Please what?"

"Don’t stop." The confession was a vapor on the cold wood. "Father, please don’t stop."

Katsuki’s rhythm stuttered, a hitch of pure, dark satisfaction. He leaned closer, his chest a hot weight against Izuku’s back. "Look at yourself. Look at your face. That’s not the face of a martyr." He ground deep, circling his hips, and Izuku’s eyes screwed shut. "Look."

Izuku forced his eyes open. In the mirror, his expression was shattered, bliss-drunk, tears cutting through the blush of exertion. He watched Katsuki’s red eyes meet his in the reflection, predatory and possessive. He watched as Katsuki’s hand left his stomach and trailed up, over his ribcage, to cup one small, soft breast. His thumb brushed over the large, puffy nipple, and Izuku jerked, a fresh wave of slickness coating Katsuki’s cock.

"So sensitive here," Katsuki murmured, rolling the tight bud between his fingers. "Such a pretty, secret little thing. And you came to my church like this. Offered yourself to God like this." He pinched, gently, and Izuku cried out. "You were always meant for a different kind of worship."

"What do you want to worship, Izuku?" Katsuki demanded, his thrusts slowing to a deep, grinding rhythm that made Izuku's toes curl against the stone floor.

"You," Izuku sobbed, the word tearing from a place of absolute truth. "I want to worship you, Father. All of it. The—the pleasure. The sin. I want to worship your cock, dripping with us. I want to taste our corruption."

Katsuki’s hand slid from his breast to his throat, fingers splaying over his pulse. "This?"

Izuku nodded, frantic, pushing back against him. "Yes. Please."

The pressure came, not brutal but absolute, a claiming squeeze that cut his air to a thin, desperate stream. Katsuki’s other hand gripped his hip, holding him immobile as he drove in to the hilt. "Then worship."

The world shattered. The choked-off cry, the blinding white heat that erupted from his core—Izuku came with a violence that ripped through him, a convulsive, soaking wave that painted the inside of the vestment case and his own thighs. His vision spotted, his body seizing around Katsuki’s cock as he squirted, the liquid release a hot, humiliating flood he could feel gushing out of him.

Katsuki hissed, his rhythm breaking into ragged, punishing thrusts. "Look at that. Look at what your worship does." His grip on Izuku’s throat tightened for a second, a final spike of dominance, before releasing.

Izuku gasped, air burning his lungs, his body still trembling through the aftershocks. In the mirror, his reflection was utterly destroyed—mouth slack, eyes rolled back, a glistening mess between his legs. Katsuki watched him, red eyes blazing, his own climax held in check by sheer will.

"You are a revelation," Katsuki breathed, his voice thick with something like awe. He leaned down, licking a stripe up the sweat-damp column of Izuku’s neck. "A perfect, profane revelation. My altar."

"Only yours," Izuku whispered, the words slurred, his consciousness floating on a sea of spent sensation. He was empty, filled, ruined, sanctified. "Always."

Katsuki straightened, his hands smoothing over Izuku’s trembling flanks. "Now," he said, his tone shifting back to command. "Clean your offering."

Izuku didn’t hesitate. He pushed himself up on shaky arms, turned, and slid to his knees on the cold floor. He took Katsuki into his mouth, the taste of himself and sweat and salt overwhelming. He worshiped.

Izuku didn't let him soften. The moment Katsuki’s climax faded, Izuku’s mouth was moving again, a desperate, sucking rhythm that drew a sharp hiss from the priest. He took him deep, his throat working open around the thick girth, gagging wetly as he forced himself down further.

“Fuck,” Katsuki breathed, his hands coming to cradle Izuku’s head, not to guide but to witness. “Look at you.”

Izuku’s eyes, glassy and green and streaming tears, rolled up to meet his. He pulled off with a slick, obscene pop, a string of saliva and spend connecting his swollen lips to the flushed, leaking head. He didn’t break eye contact. He dove back down, hollowing his cheeks, his tongue a frantic stripe along the underside where the vein throbbed.

“You’re sucking my soul right out of my cock,” Katsuki muttered, his voice ragged. He watched, transfixed, as Izuku worshiped with a sloppy, choking abandon that was beyond hunger. It was annihilation.

Izuku came up for air, gasping, spit dripping from his chin. “It’s all I am for,” he rasped, his throat raw. “For this. For you.” He took him in again, deeper, his nose pressing into the coarse blond curls at the base. His body convulsed with the effort, but he didn’t pull back.

Katsuki’s fingers tightened in the green curls. The demon in him, the chaos, reveled in the violation. But the man—the sliver of the priest he used to be—stared down in shock and a dark, dawning awe. This wasn’t just corruption. This was devotion, twisted and magnificent. “You beautiful, ruined thing,” he whispered.

Izuku increased his pace, a wet, rhythmic slapping sound filling the sacristy. His hands came up to cradle Katsuki’s heavy sac, rolling the tightness there, and Katsuki’s hips jerked forward involuntarily. “Enough.” The command was rough, but his hands were gentle, trying to pull Izuku off.

Izuku resisted, a muffled sound of protest vibrating around him. He sucked harder, his throat fluttering, a silent plea.

“I said enough.” Katsuki pulled him free, his cock slick and fully hard again, bobbing against his stomach. Izuku knelt, panting, his face a mess of tears, spit, and his own submission. “You want it that badly?”

“Yes,” Izuku whimpered, his hands trembling as they reached. “Please, Father. Let me have it. Let me have all of you.”

Katsuki’s red eyes glowed faintly in the candlelight. A low, inhuman rumble built in his chest. “Then have it.” He fisted his hand in Izuku’s hair and guided himself back into that willing, wrecked mouth, setting a brutal, shallow pace that punished Izuku’s lips and tongue. “Take it. Drink me down. This is your communion.”

Izuku’s eyes fluttered shut, then snapped open, holding Katsuki’s gaze as he was used. He took every thrust, the head of Katsuki’s cock hitting the back of his throat until his eyes watered anew. He swallowed convulsively, a willing vessel.

Katsuki felt the coil tighten, a second, sharper climax ripped from him by the sheer force of Izuku’s surrender. “Now,” he snarled, and pushed in deep, holding Izuku there as he pulsed. Izuku’s throat worked, swallowing every drop, a desperate, grateful sound escaping his nose. When Katsuki finally pulled out, Izuku sagged forward, catching himself on Katsuki’s thighs, breathing in ragged, wet gulps of air.

Katsuki looked down at the wreck of a boy at his feet, at the absolute, utter conquest of it. The demon purred in satisfaction. The priest felt a crack in the foundation of his own damnation. He smoothed a thumb over Izuku’s bitten, red lip. “No one will ever worship you like I ruin you,” he said, the truth of it hanging in the incense-thick air.

"You can do whatever you want to me, Father."

Izuku’s voice was a raw, wrecked thing from the stone floor. He looked up, his green eyes holding no defiance, no fear—just a vast, hollowed-out devotion.

Katsuki stared down at him. The candlelight caught the demon-red in his gaze, but something flickered behind it. He crouched, bringing them eye level. His hand came up, fingers tracing the tear-tracks on Izuku’s cheeks. “I know.”

“I mean it,” Izuku whispered, leaning into the touch. “Anything. Here. Anywhere. You don’t… you don’t have to threaten me anymore.”

“Is that so?” Katsuki’s thumb pressed against Izuku’s bottom lip, still swollen and wet. “You’re offering your damnation freely now?”

“It’s not damnation.” Izuku’s breath hitched. “It’s my purpose. You showed me.”

A low sound rumbled in Katsuki’s chest. He stood, his shadow swallowing Izuku whole. “Get up. On the table.”

Izuku moved, limbs shaky but obedient. The polished oak was cold against the backs of his thighs as he sat, then lay back. The candle’s flame danced in his eyes. Katsuki stood at the end of the table, looking down the length of his body.

“Spread your legs.”

Izuku did, letting his knees fall open, exposing himself completely to the cool air and the hotter gaze. Katsuki’s eyes drank in the sight—the soft, freckled thighs, the mess of release glistening in his curls, the small, pretty pussy still flushed and open.

“You’re a vision,” Katsuki said, his voice stripped of its earlier taunt. It was just awe. He placed a hand on Izuku’s inner knee, pushing it wider. “My most sacred blasphemy.”

He leaned over, but not to kiss him. He lowered his head between Izuku’s legs. The first flat stroke of his tongue made Izuku jolt, a sharp cry echoing off the stone.

“Oh God—”

“Not God,” Katsuki murmured against his skin, his breath hot. “Just me.” He licked again, a slow, deliberate stripe from his entrance to his enlarged clit, and Izuku’s back arched off the table.

It was obscene. The wet, sucking sounds, the way Katsuki’s tongue speared inside him, fucking him with it, then circled that sensitive nub with relentless focus. Izuku’s hands scrambled, finding nothing to grip but smooth wood. “Katsuki—Father, please—I can’t—”

“You can.” Katsuki pulled back, his lips shining. “You will. You’ll come for me again. On my tongue. In my church.” He dove back in, sucking the tender flesh into his mouth.

Izuku sobbed, his hips lifting off the table, seeking the pressure. It built too fast, a second climax coiling in his gut, sharp and impossible. His fingers tangled in Katsuki’s spiky hair, not to push him away, but to hold him there. “I’m gonna—I’m—”

Izuku’s cry shattered into a broken, wordless scream as the climax tore through him. His back bowed off the cold oak, his fingers scrambling against the polished surface. A hot, gushing rush flooded Katsuki’s mouth—salty and sweet and utterly profane.

Katsuki didn’t pull away. He drank it down, his throat working, his tongue lapping at the pulsing source as Izuku shook apart beneath him. He sucked, gentle then greedy, until Izuku was sobbing from overstimulation, his hips trying to twitch away.

“Stop—too much—Katsuki, please—”

Katsuki lifted his head, his lips glistening. “This,” he rasped, his voice thick. “This is my altar wine.” He leaned in, capturing Izuku’s mouth in a deep, claiming kiss, making him taste his own release mixed with Katsuki’s spit.

Izuku moaned into the kiss, his body going pliant and boneless. When Katsuki broke away, Izuku’s eyes were unfocused, his chest heaving. “You… you drank it.”

“Every drop.” Katsuki’s thumb swiped over Izuku’s wet lower lip. “Your offering. Your sacrament. You give it, I consume it. That’s the ritual now.”