Chapter Text
If you wish to find out how to support my work and read the next five chapters in advance, then please visit: https://twitter.com/accio__dracarys
The atmosphere in Gym Gamma was thick with the sound of heavy breathing and the rhythmic thud of bodies hitting mats. Aizawa-sensei and All Might had organized a special training session for Class 1-A: one-on-one sparring matches. While the brackets felt similar to the Sports Festival, the rules had been stripped down to the basics. There were no ring-outs to save anyone today; a match only ended when a student was successfully subdued or forced to "tap out."
"Next up!" All Might called out, his voice echoing off the reinforced walls. "Kirishima versus Tetsutetsu! And over on Mat B, Uraraka versus Jiro!"
The gym was a flurry of activity. Jirou went straight to the attack, sending her earphone jacks snaking across the floor, forcing Uraraka to leap and weave in a desperate attempt to close the distance without being blown back by a sound wave.
Izuku stood at the edge of the main mat, his heart hammering a frantic rhythm against his ribs. He was checking his gloves, so lost as his mind raced through different strategies, that he didn’t realise when the match ended.
"Midoriya. Yaoyorozu. You're up," Aizawa announced, his eyes glowing faintly as he watched the previous match wind down.
Momo stepped onto the mat opposite him, her stance poised and intelligent. Her dark eyes, usually so composed, held a glint of competitive fire. "Good luck, Midoriya," she said, a small, confident smile playing on her lips. "I won't make it easy."
"You too, Yaoyorozu," Izuku replied, trying to match her composure, but his heart was already thudding a frantic rhythm against his ribs.
All Might gave the signal. "Begin!"
Izuku launched forward, channeling a controlled burst of One For All: Full Cowl at 10%. He was fast, a blur of green, aiming to close the distance. He knew Momo’s weakness: she needed time to create. If he could get close, if he could pin her…
But Momo was faster than he’d anticipated. With a flick of her wrist, a heavy, telescopic bo-staff slid into her grip from her palm. She didn't move toward him; she moved away. With a graceful pivot, she used the staff to vault over his initial lunge, creating a wall of flash-frozen resin between them before she even hit the ground.
Izuku grunted, punching through the resin, but Momo was already five steps back. She was a blur, her hands moving over her skin as she produced a series of small, weighted bolas. She threw them with surgical precision, forcing Izuku to twist mid-air to avoid being tangled.
She’s playing chess, Izuku thought, gritting his teeth. And I’m just trying to tackle her.
He unleashed a series of air flicks, trying to disrupt her, force her to create defensively. But Momo simply formed larger, thicker shields, shrugging off the pressure. Each dodge, each blocked attack, fueled a simmering frustration within Izuku. He was expending energy, getting nowhere.
"You're rushing, Midoriya. It’s becoming too predictable," Momo said, her voice calm and steady. Every time he got close, she created a new obstacle… a slick of oil on the floor, a blast of high-pressure CO2, or a reinforced shield that forced him to lose his momentum.
Predictable? The word grated on him. He felt a surge of something hot and unfamiliar in his chest. It wasn't just the desire to win; it was a deeper, more primal urge. He needed to stop her.
More than just defeat, he needed to control her.
I need to bind her, he thought, his jaw tightening. I need to make her stay still.
He pushed his legs harder, the green lightning of Full Cowl flickering violently. He feinted left and leaped right, but Momo had already created a net-gun. THWIP. The net expanded in mid-air. Izuku tore through it with his bare hands, but the delay was enough for her to retreat again. She was smiling now—a small, knowing smile that said she had him exactly where she wanted him.
Enough, Izuku thought. The frustration in his chest shifted from heat to something cold and dark. Hold her down. Stop her. BIND HER.
Then it happened.
Thick, oily coils of black energy erupted from his skin. They didn’t feel like his normal quirk, but violent, and lashing out with a mind of their own. The sheer force of the manifestation cracked the floor beneath him, sending shards of concrete flying.
"Whoa! Young Midoriya!" All Might shouted, his smile vanishing as Aizawa was looking to rush forward and intervene. The black whips were spiraling out of control, whipping through the air with enough force to shatter the gym’s equipment.
Momo gasped, stumbling back as the dark energy tore through her latest shield like it was paper. "Wait! Sensei, don't!" she called out, sensing the raw, primal nature of the power. "I can handle this! Midoriya"
One whip snaked towards her, moving with terrifying speed. She instinctively dodged, rolling back, trying to create a barrier, but the tendrils were too fast, too numerous. They were enveloping her from all sides.
She created a massive net launcher, firing a heavy-duty capture net at the wild black whips. But the tendrils merely sliced through it, then continued their relentless pursuit. They moved like a predator, focused, relentless.
They coiled around her ankles first, a sharp tug that brought her off balance. Then around her waist, surprisingly gentle yet undeniably firm. More whips emerged, wrapping around her arms, pinning them to her sides. She felt herself lifted, suspended in the air, the powerful tendrils binding her limbs and torso. She was completely at his mercy, hanging mid-air, her body held in a complex, almost artistic pattern of black energy.
Izuku’s breathing was ragged, his eyes wide, a strange mix of terror and triumph in their depths. The wild energy of Blackwhip began to recede, coalescing, becoming still and obedient, perfectly holding Momo in its grasp. He felt the control return, a cold, focused clarity.
He walked forward, stepping into the space directly beneath the suspended, bound girl. Momo was flushed, her chest heaving against the tight constraints of the black whips. She looked down at him, her eyes wide, her heart racing not from fear, but from the overwhelming sensation of being utterly dominated by his will.
"There," Izuku said, his voice low, firm, and utterly devoid of his usual nervous stammer. The words were a quiet declaration, a promise, a command. "Now you can't move."
Momo couldn't find the words to reply. She just bit her lip, a traitorous thrill running through her as she realized she didn't want him to let go.
The hum of the gym’s ventilation system was the only sound for a long, heavy moment. The black tendrils slowly lowered Momo until her boots touched the mat, but they didn't retract immediately. They pulsed once, giving a final, lingering squeeze before dissolving into Izuku’s skin.
Aizawa stepped forward, his eyes narrowed as he deactivated his quirk, though it hadn't been needed to stop the whips once Izuku gained control. "Match over. Winner, Midoriya." He paused, looking between the two. "Both of you. Recovery Girl. Now."
"I'm fine, Sensei," Izuku said quickly. His voice was still deeper than usual, grounded by a new sense of gravity. "I just... I need to process this."
Momo, her face still dusted with a deep crimson, straightened her tactical vest. Her legs felt slightly weak, but she nodded in agreement. "I am uninjured as well, Aizawa-sensei. There is no need for a medical intervention."
All Might began to bustle over, his face a mask of paternal worry. "Young Midoriya! That power, it was… we need to talk about the vestiges—"
"Later, All Might," Izuku interrupted, not unkindly, but with a firm finality that made the hero blink in surprise. "Please. Just... later."
Aizawa sighed, rubbing the bridge of his nose. He could sense the strange, charged energy still vibrating between his two students. "Fine. You’re both dismissed. Given the... intensity of that spar, you can return to the dorms early to rest. The rest of the class will finish the rotation."
__________________________________________________________
The walk back to Heights Alliance was silent. Izuku kept his hands shoved deep in his pockets, his mind a whirlpool of conflicting sensations.
He had always wanted to be a hero who saved people with a smile. But in that gym, when Blackwhip had emerged, he hadn't felt like a savior. He had felt like a conqueror. The frustration of being unable to touch Momo had morphed into a dark, possessive need to see her still. To see her bound. To see her submit.
And the most terrifying part is that he didn't regret it. The memory of her suspended in his energy, helpless and looking at him with wide, trembling eyes, sent a jolt of heat through him that made his pulse race.
He didn't go to the common room. He went straight to his floor, needing the isolation of his own four walls to deal with the flickering black static still dancing under his skin.
__________________________________________________________
Across the hall in the girls' wing, Momo Yaoyorozu was having a very different struggle.
She had locked her door and leaned against it, her breath coming in shallow hitches. She closed her eyes, and all she could see was the dark, predatory focus in Izuku’s gaze. She could still feel the phantom pressure of the black whips. The way they had mapped the curves of her body, the way they had forced her arms behind her back, leaving her completely exposed and vulnerable.
"Oh, heavens..." she whispered, her knees finally giving way.
She crawled onto her bed, her heart hammering. She tried to think about the tactical errors she had made, but her mind kept drifting back to the sensation of the energy pulsing against her skin. It had been so warm. So absolute.
A low shiver traveled down her spine. Her hand snaked down, sliding beneath the waistband of her training shorts. Her fingers began to rub slow, rhythmic circles, her eyes fluttering shut. She imagined the whips returning—not in a gym, but here. She imagined Izuku not letting go. She imagined him leaning in close, his breath on her ear, telling her she was his to hold.
Knock. Knock.
Momo bolted upright, her heart nearly leaping out of her chest. "W-who is it?"
"Yaoyorozu? It’s Izuku. Can I... can we talk?"
Panicking, Momo scrambled to pull her duvet over her lap, tucking it tightly around her waist to hide her disheveled state. "Yes! Just- just a moment! Come in!"
The door creaked open. Izuku stepped in, looking smaller than he had in the gym, but that new spark was still in his eyes. He stayed near the door, looking guilty.
"I wanted to apologize," he said softly. "My quirk... it mutated. It reacted to my emotions, and it was out of control. I didn't mean to—"
"It’s fine, Izuku," she interrupted, her voice a bit breathy. She used his first name without thinking. "I told you in the gym, I could handle it. I wasn't hurt. Truly."
Momo gripped the blanket tighter. Her mind was racing. "Are you going to try using it again?
"Yes," he said, a small frown forming. "Yes I have to in case a repeat of this happens. But I need to practice with it in a controlled environment so I don't lose my head next time."
Momo felt a surge of boldness, fueled by the lingering heat in her blood. "Then practice with me."
Izuku’s head snapped up. "What? No, I could hurt you, I—"
"You won't," she said, her voice growing more confident as she saw the flicker of interest in his eyes. "I can create whatever restraints or padding we need. And besides... I’m the only one who knows how it feels when it’s active. Let me help you master it, Izuku."
Izuku stared at her for a long moment. The silence in the room grew heavy, thick with the same tension that had filled the gym. Finally, he nodded slowly.
"Okay," he whispered. "We'll practice after classes. Thank you, Momo."
He turned and left, closing the door softly behind him.
Momo stayed frozen for a second, then collapsed back onto her pillows with a ragged moan. The thought of a "practice session", of being bound by him again, but this time intentionally, sent a fresh wave of heat through her.
Her hand found its way back beneath her shorts, her movements more urgent now.
"Izuku..." she whimpered into the quiet room, her body arching as she surrendered to the memory of his command.