[A/N: I guess Webnovel is full of Saints who can't handle a little Netori. It's not even targeted towards any of you. We don't even know Masaru. Shanks left arm had more story than Masaru. It's not even that deep. This is fiction. ]

"Katsuki, Izuku left!" Mitsuki shouted toward the kitchen as she and Izuku walked down the hallway.

No response came — just the faint sound of music through his headphones and the clack of a knife on a cutting board. Katsuki smirked to himself, focusing on his sandwich and tuning out the world.

'I need to get stronger. From today, I'll train in martial arts.' he thought, a determination burning quietly behind his eyes.

Upstairs, the air felt different — quieter, heavier. Izuku followed Mitsuki to the end of the hall until she stopped in front of a door and pushed it open.

Inside was her and Masaru's bedroom — neat, warm, and ordinary… at first glance. But Izuku's sharp eyes picked out little details immediately. The way the bedspread was slightly rumpled. The faint scent of her perfume hanging in the air. And there, on the bed the exact spot he recognized from the teasing video call they had— the same soft lighting, the same sheets.

The memory made his pulse quicken despite himself.

While Izuku was taking it all in, Mitsuki's mind was racing too. She felt a twinge of guilt deep down, a whisper of conscience reminding her that this was her son's childhood friend — and that once they crossed this line, there would be no turning back.

But guilt was a small, fragile thing compared to the rush she felt now.

Because above all else, Mitsuki wanted to see him break. She wanted to see Izuku — strong, stubborn Izuku — squirm under her touch, his voice trembling, his composure shattering.

That thought alone sent a shiver of heat curling through her.

Most people didn't know the truth about her — that behind her blunt attitude and sharp tongue, Mitsuki was a dyed-in-the-wool sadist. She thrived on drawing reactions out of people, pushing them until pleasure and pain blurred into something intoxicating. Poor Masaru hadn't stood a chance — he'd learned to take her roughness, even grow to enjoy it, but it had taken years.

Now, standing in front of someone younger, stronger, and so full of nervous tension, she could hardly wait to see how Izuku would look when that confidence cracked.

'If he begs the way I think he will… that sight might make me climax harder than I ever have in my life.' The thought made the corner of her mouth curl upward into a slow, dangerous smile.

[Headcanon]

Izuku couldn't see the small, dangerous smile curling at Mitsuki's lips — and he knew nothing about her kinks. All he knew was that he wanted to get laid.

"Alright… let's begin, shall we?" he said with a confident smirk, his hand suddenly coming down on her ass with a sharp SMACK.

The sound echoed in the quiet room. Mitsuki's eyes went wide — the sting barely registering before a hot, unexpected rush shot through her.

'What the hell was that?' she thought, trying to ignore the way her pulse quickened.

She masked it with a scoff and spun around, shoving him back against the wall with both hands. "Alright… let's begin," she shot back, her smirk returning.

Her hand slid down without hesitation, grabbing a handful of his crotch. The moment she felt the weight and size under her palm — and it wasn't even hard yet — her breath caught.

An unbidden image flashed in her mind — Izuku, over her, thrusting hard, stretching her in ways Masaru never could.

She stepped back abruptly, heat flooding her cheeks. 'What is wrong with me? I never… never felt this way with Masaru.'

"Looks like you're not willing," Izuku said flatly, turning toward the window. "Call me when you're serious about this relationship, Mitsuki."

"Wai—" she began, but her words cut short when he suddenly spun back, grabbed her, and crushed his lips to hers.

Her eyes widened, her body frozen in shock for a heartbeat before instinct took over and she melted into the kiss. His hands slid to her thighs, lifting her with ease. Her legs wrapped around his waist as he carried her to the bed, never breaking the kiss — his lips pressing harder, more urgently.

As they landed on the mattress, his hand trailed down her side, slipping over her stomach, until it cupped her mound through her pants. Without breaking rhythm, he began moving his palm in slow, deliberate circles, pressing just enough to make her squirm.

Mitsuki bit back a moan — but the heat pooling between her legs betrayed her. Her quirk only heightened her sensitivity, making each motion sharper, hotter.

Izuku smirked against her lips when he felt the dampness soaking through. He pulled back just enough to whisper, voice low and taunting:

"You wanna cum?"

She wanted to deny it. She wanted to play the sadist, keep control. But her body was already trembling.

"I didn't think… you had the qualities to make me—" Her voice broke mid-sentence as the pleasure spiked, her breath hitching hard.

Izuku chuckled, kissing her again as his fingers worked faster through the fabric, rubbing her clit in perfect, merciless circles. Her body tensed — the burn in her core swelling, cresting, ready to break.

And then… he stopped.

Completely.

Her climax was ripped from her in an instant, leaving her body throbbing and empty. She stared at him in disbelief. "What?! I was just about to—"

"Cum?" he cut in, smirking.

Her face flushed hot. "N-no, of course not," she muttered, hastily straightening her clothes.

Without another word, he got up, crossed to the window, and stepped onto the sill.

"See you later, Mitsuki," he said with a grin, before dropping down and vanishing from sight.

She sat there in stunned silence. The breeze from the open window slipped between her legs, cooling her still-damp folds, making her shiver.

She turned onto her side, staring at the last traces of daylight outside. And that's when it hit her — a wave of raw, gnawing frustration so intense it almost made her shake.

'I need to climax.'

Her jaw clenched. Without a second thought, she got up, locked the door, and grabbed for the nightstand drawer.

Mitsuki slid the drawer open, pulling out her trusty toy — one that had never failed her before. She tossed herself back on the bed, ripping her pants down to her knees, not even bothering to take them off fully.

Her fingers brushed over her folds and she winced at how sensitive she still was. She was soaked — more than she had been in a long time — but it wasn't from her own doing. It was him.

Her jaw tightened. 'Just finish it. Get it over with.'

She pressed two fingers inside and started working herself quickly, her other hand rubbing her clit. The familiar motions should have been enough, but every time her body climbed toward release, her mind flashed back to his hand — the way his fingers knew exactly where to press, the deliberate pace, the smug grin on his face when he stopped.

The memory didn't help — it haunted. She wanted that same burn, that same maddening push toward the edge, but her own hand felt dull, mechanical.

Minutes passed. Her breathing grew heavier, but the rush… the spark wasn't there.

"Dammit…" she muttered, frustrated, forcing herself to go harder — until she suddenly stopped, the disappointment washing over her like cold water.

She dropped her toy beside her and lay back, sprawled out on the bed, staring at the ceiling. Her thighs glistened, her chest rose and fell, but her expression was pure irritation.

The room was silent, save for her shallow breaths.

'He's in my head now…' she realized bitterly.

Outside, the last rays of sunlight faded into night. Mitsuki didn't move. She just lay there, legs still spread, the air cooling the dampness between her thighs, her body aching for a release she couldn't give herself anymore.

TO BE CONTINUED

[A/N: now thays how you tame a sadist. Class dismissed]