Chapter Text
They developed a routine. A secret, filthy, perfect routine.
Every day, they found somewhere new. The empty classroom on the third floor. The locker room during lunch. The library stacks in the back corner where no one went. Katsuki would corner Izuku, would back him against a wall or bend him over a desk, would fuck him quick and dirty or slow and deep, depending on how much time they had.
Izuku learned that Katsuki loved to talk. Loved to whisper filth in his ear while he fucked him, telling him how good he felt, how tight he was, what a perfect little cockslut he'd become.
"You live for this, don't you?" Katsuki would growl, pounding into him from behind in the empty classroom. "Live for my cock. You're addicted to it. Can't go a day without being filled, can you?"
"No," Izuku would gasp, his hand working his clit, his cunt dripping around Katsuki's shaft. "Can't... I need it... need you..."
"That's right. You need me. This pussy is mine now. Say it."
"Yours," Izuku would moan, coming hard, his cunt spasming around Katsuki's cock. "Yours, yours, only yours–"
And Katsuki would follow him over the edge, marking him, claiming him, making him his.
But it wasn't just sex. Somewhere along the way, it became more.
Katsuki started walking him to class. Started leaving notes in his locker– filthy, graphic notes that made Izuku blush and squirm, but notes nonetheless. Started bringing him coffee in the morning, exactly how he liked it, with two sugars and extra cream.
Izuku started waiting for him after practice. Started wearing Katsuki's baseball jacket around school, drowning in the fabric, smelling like him. Started looking up when he walked into a room, seeking out those red eyes, finding them already watching him.
They still hid. Still kept their secret. But the lines were blurring.
One night, a month into whatever this was, Katsuki showed up at Izuku's window. He climbed the tree outside, tapped on the glass, and Izuku let him in with shaking hands.
They didn't fuck. They lay in Izuku's narrow bed, fully clothed, and talked. About their fears. About the future. About what would happen when graduation came and Katsuki went off to college and Izuku went... somewhere.
"I don't want this to end," Katsuki admitted, his voice soft in the darkness. "I don't want to lose you."
"Then don't," Izuku said, turning to face him. "Come with me. Wherever I go. Or I'll come with you. I don't care about college, Katsuki. I care about you."
Katsuki kissed him then– sweet, tender, nothing like the desperate collisions of their secret encounters. "I love you," he whispered against Izuku's lips. "I know it's fast. I know it's crazy. But I love you, Izuku. You're mine. You've been mine since the moment I heard you moan in that hallway."
"I love you too," Izuku breathed, tears in his eyes. "I've loved you since you kissed me in that shed. Since before I knew what love was."
They fell asleep tangled together, and in the morning, when Izuku's mother knocked on the door with breakfast, Katsuki didn't hide. He sat up, ran a hand through his messy hair, and said, "Morning, Mrs. Midoriya. I'm Katsuki. I'm your son's boyfriend."
Inko Midoriya had looked at them– at Izuku's flushed face, at Katsuki's possessive arm around her son's waist, at the love visible in every line of their bodies– and smiled.
“Breakfast is ready. Bring your young man downstairs, Izuku."
They decided to do it on a Monday.
Katsuki walked into school holding Izuku's hand. No warning. No announcement. Just... walked in, their fingers intertwined, his thumb stroking Izuku's knuckles.
The reaction was immediate. Whispers. Stares. Shock.
Katsuki Bakugo, the sex god, the player, the untouchable star athlete... holding hands with Izuku Midoriya, the invisible nerd, the weird quiet kid, the boy no one noticed?
"Is this a joke?" one of Katsuki's teammates asked at lunch, staring at them sitting together at the jock table, Izuku blushing furiously but not letting go of Katsuki's hand.
"Does it look like a joke?" Katsuki asked, bringing Izuku's hand to his lips and kissing his knuckles. "He's mine. I'm his. Get used to it."
"But... him?" The teammate gestured vaguely at Izuku. "He's..."
"He's perfect," Katsuki interrupted, his voice going dangerous. "He's smarter than you. He's braver than you. And he's better in bed than anyone I've ever been with. So shut the fuck up before I make you."
Izuku hid his face in Katsuki's shoulder, embarrassed but glowing.
The rumors started immediately. About how Katsuki had been seen fingering Izuku in the hallway. About how they'd been caught fucking in the equipment shed. About how Izuku had some kind of magical power that had tamed the untamable Katsuki Bakugo.
Izuku didn't care about the rumors. He only cared that Katsuki didn't let go of his hand. That Katsuki kissed him in the hallway between classes. That Katsuki sat with him at lunch, fed him fries, whispered filthy promises in his ear that made him squirm.
They were still careful about the sex in public places– getting caught by a teacher would be disastrous. But they didn't hide their relationship. Didn't hide their love.
Katsuki wore Izuku's bracelets to practice. Izuku wore Katsuki's letterman jacket everywhere. They walked through the halls like they owned them, like they were the only two people in the world.
And sometimes, when the bell rang and the halls emptied, Katsuki would push Izuku against his locker and kiss him senseless, would slide his hand down Izuku's pants and make him cum with his tongue in Izuku's mouth, would whisper, "Mine, mine, mine," until Izuku was trembling and begging for more.
"Love you," Izuku would gasp, wrecked and happy.
"Love you more," Katsuki would reply, fixing Izuku's glasses, smoothing his hair.
They were different now. Katsuki was softer around the edges, his anger tempered by someone who saw him clearly. Izuku was brighter, more confident, walking with his head up instead of down.
They fit. In all the ways that mattered, they fit.
They stood on the stage together three months later, receiving their diplomas.
Katsuki had turned down two scholarships to stay local– there was a state school with a good baseball program, close enough to commute. Izuku had gotten a full ride to the same school, academic scholarship, pre-med.
They had an apartment lined up. A tiny one-bedroom with good light and a big bed. A place where Izuku could be loud, could scream when Katsuki fucked him, could squirt all over the sheets without worrying about getting caught.
As they walked off the stage, as the crowd cheered, Katsuki pulled Izuku into his arms and kissed him in front of everyone– their parents, their classmates, the principal.
"Ready for the rest of our lives?" Katsuki asked, his forehead pressed to Izuku's.
"With you?" Izuku smiled, bright and beautiful and finally, finally seen. "Always."
They walked off together, hand in hand, into a future that was wide open and full of promise.
And when they got home that night, when Katsuki laid Izuku out on his childhood bed and made love to him slow and deep and perfect, when he filled him up and whispered, "Forever, you're mine forever," Izuku knew that invisible boys didn't always stay invisible.
Sometimes, they became everything.